Getting older

It’s seems like as soon as I hit a certain age my body decided it’s not going to take this shit anymore. Everything seems to upset my stomach except salad. Cheese or to much pasta kills me. Meat goes right through me. My back is weak I tried exercising my knee ended up hurting and it freaked me out so I stopped. I was fine then it was like all the sudden everything hurts or upsets my body. Hurt my neck the other day I don’t even know how. I have some shit on my hand cut i don’t know where it came from. I keep finding bruising on my legs. I wake up and am still exhausted. I don’t know what is normal never been like this before. Fucking sucks