Feeling stuck.

I apologize if this isn't the place for this or if this is a mess to read. I've had a LOT of stomach issues growing up with my illness. So I was always a bit on the smaller side. But as time has went on I've started gaining more weight. Which isn't a problem. But I've noticed my fatigue and pain increasing as well. I work in a warehouse for 9+ hours a day. So I know that's part of it. The thing is I want to try to get better. I used to be pretty fit before I got sick. But now even the smallest exercises feel like I'm going up a mountain. I just don't really know what to do or where to start. I don't want to make myself worse by not putting in the effort. But some days it feels absolutely impossible. I don't really know what I'm looking for. Advice maybe? Maybe just knowing I'm not alone in this feeling. It's hard to find that motivation when doing what is supposed to be helping feels just as painful. I just feel stuck. But maybe im just lost in feeling sorry for myself? I dunno.