Started exercising and health anxiety is back

Hey, I’m going through some new health anxiety worries (ALS and MS) now that I’m exercising again. I’ve been swimming every week for two months and noticed my legs very shaky and stiff when I get out of the pool. Normal, I thought. I haven’t exercised properly for over five years. I’m 37 so I am also dealing with aging and potential covid fatigue, but back to the symptoms… Things seemed okay mentally, but then I noticed my right leg feeling a little ‘slower’ than the left when I walked. I can’t explain it very well, but it’s like the coordination isn’t quite right. I put it down to exercising and stretching the hip joint which I haven’t done all these years mostly sedentary. But after a couple more weeks I googled it (noooo) and now freaking out about ALS and MS. I feel like it’s getting worse and I worry I am going to fall over. I’m even scared to walk because it triggers the symptom (which moves from hip to knee and now to left leg).

Logically, all signs point to anxiety, but I can’t seem to shake that something is seriously wrong. I’m so scared and hating life. This happens every time I try regularly exercising… I feel good for the first few weeks, then freak out over an injury or weird sensation and feel not exercising is just better for me mentally. But the long term implications of not exercising upset and scare me. I’m gaining weight and want to feel happier and healthier. I don’t know if anyone else hits this kind of wall with exercise but I’d like to know. I don’t really want to go to the doctor yet because I’m 99% sure this is anxiety again (it always is) but that 1% is frightening.