Feeling weak, muscle aches, joint stiffness, and sudden weight gain... anyone else?

Man, I’ve been feeling incredibly weak for about 6 months now. At first, it wasn't even that bad—just felt slightly off within normal limits—but lately, things have been spiraling and I’m starting to think there’s something seriously wrong with me.
Like, if I go for an hour-long walk, my muscles are so wrecked for the next two days that I can barely move. If I just swing my arms around, my forearms are sore the next day... basically, whatever I do, I wake up the following morning feeling like I've been hit by a truck.
I honestly thought maybe my diet was just trash, so I started loading up on magnesium, minerals, vitamins, the whole nine yards...
But nothing worked. Not a thing. I went in for blood work and everything came back perfectly fine—actually, the doctors said the results were great, which makes zero sense given how I feel.
They suggested I see a neurologist, but when I finally sat down with him, he basically brushed it off, saying it wasn't his department and told me to go see an immunologist instead.
I did a little digging online, and honestly... I'm terrified because it looks like it could be some kind of muscular dystrophy.
I’m only 19, I don't touch alcohol or cigarettes, and I used to be pretty active with sports—now, though, that's just impossible.
To make matters worse, I’ve gained 20 pounds in just the last month.
Does anyone have any idea what could be going on? What should I be doing while I wait for this appointment with the immunologist? And is there any chance I can actually get back to how I used to be?

bluewalker9 said:For six months now, I’ve just felt weak. At first, everything seemed within the normal range, but things have been spiraling lately, and I'm starting to think there's an underlying illness left unchecked.
If I go for an hour-long walk, my muscles are so inflamed for the next two days that moving becomes a struggle. If I do any manual work, my forearms are sore the very next day. No matter what I do, the muscle soreness follows me like a shadow.
I initially assumed it was just my diet, so I started loading up on magnesium, minerals, vitamins, and all that stuff...
But nothing worked. I went in for blood work, and the results were perfectly fine—actually, they looked great.
The doctors suggested I see a neurologist, but when I finally sat down with him, he dismissed the idea, saying it wasn't his field, and told me I should probably see an immunologist instead.
I did some digging online, and honestly, it feels like I might be dealing with some form of muscular dystrophy.
I’m 19 years old. I don't touch alcohol or cigarettes. I used to play sports recreationally, but now, it's physically impossible.
On top of everything, I’ve gained 20 pounds in the last month alone.
Does anyone have any idea what could be going on? What should I be doing while I wait for my appointment with the immunologist? Is there any chance my body can get back to how it used to be?

I would personally get my hormone levels checked. I’d also schedule an abdominal ultrasound... to me, this whole thing screams excess cortisol or something involving the adrenal glands—maybe Houston syndrome.
You definitely need to see both an internist and an endocrinologist. I'm not sure if an immunologist is even the right specialist to handle this given how backed up they usually are.

Honestly, I’m at a total loss. I don't even know who else to turn to, so I figured I’d just post here and see if anyone has some advice. For a while now, my strength and endurance have just completely tanked. It’s frustrating because I’ve put in the work—I lift weights regularly, I get my steps in, and I try to eat clean. I used to be able to pack on muscle and actually see progress, but lately, it feels like I’m just moving backward. I feel weak all the time. I'm struggling with basic lifts, and if I even attempt a light workout, I’m totally wiped out after just two minutes. To make matters worse, I'm gaining fat around my stomach, hips, and chest—it's getting to the point where it looks almost feminine because that's where everything settles—while I'm simultaneously losing muscle mass in my arms and legs. It's a nightmare. I've already gone through the ringer with doctors. I had blood work done, an ultrasound of my thyroid, heart, and abdomen, and everything came back normal. I’ve been feeling so low and exhausted that I eventually saw a neuropsychiatrist. They prescribed me some Deprozel, which has helped a little bit, but that crushing, chronic fatigue and lack of energy hits me the second I wake up in the morning. I’m thinking about getting my hormone levels checked next. If my testosterone and everything else comes back fine, I honestly won't know what to do. Does anyone have any advice on how to deal with this stubborn fat gain or how to rebuild muscle in my limbs and upper body? My bones even seem thinner and weaker lately. It's gotten so bad that even chewing food feels like a struggle because my jaw muscles feel so weak. Please, if you have any ideas, let me know.

No matter what I do, my muscles just absolutely wreck me afterward
Like, if I manage to squeeze out even 10 pushups, my chest is killing me for five days straight—and it’s the same story with every single muscle group
I can barely move... plus, I’ve somehow put on 20 pounds because of this whole mess
I’ve already been to see an immunologist, a neurologist, and an endocrinologist, but according to all of them, my labs and tests look perfectly fine
Does anyone actually have a clue what could be going on here?