I would think that your fatigue could be explained by how exhausting it is to take care of someone all night and all day without stopping. I would more think it could have something to do with having some degree of depression, because, well, why wouldn't you? Life has thrown you an enormous curve ball. It is emotionally exhausting to wonder where things are going, how you'll get there, what will happen next, is there a fast ball coming, etc, etc. I'm glad you've made an appointment to see your doc. Please discuss all your symptoms with him/her, and see if getting on an anti-depressive and hooking up with a counselor just might make some sense. There is NO SHAME in that! It is, in fact, the emotionally healthy thing to do.
Best of everything to you, dear.
58 yo Type1 DM 48 years
12/09 Stage IV 2/22 nodes + liver met, colon resec
3 tx FOLFIRI, liver resec 4/10
9/10 6 mos off chemo, Neg PET&CTC CEA nl
2/11 finished total 10 rounds chemo
9/13 ^17th clean PET/CT NED for now