Seeing my General Practice dr Monday

I am going into see my GP Monday just for routine work up to keep my referral going for my GI. Ironically enough except for my crohns I never seem to be sick but they like me to come in at a minimum of at least every other year. I am feeling much improved after my last flare oin October but still have just a lingering feeling of fatigue. Not debilitating by any means but the kind that if I were to recline in a chair I would probably be asleep within 15 mins. Since I have to go to see the dr I thought I would ask for bloodwork to be done. My GI just ran a metabolic panel to check my liver and they did a C-reactive protein test. But no other check as far as iron levels or anything else. I am going to have my GP run an iron (I have a history of anemia)' vitamin D and Vitamin B12 test. Does anyone have any ideas on anything else I might want to ask for? I suspect my Iron is low because I can't tolerate iron supplements and give up on them a few months in..but I really really want to get my full energy back. Ironically I know that light work outs will help but can't even seem to muster the motivation for that. I seem to have fallen into a funk. Not sure if it is truly something wrong or just winter blues.
Any advise on lab work to ask for is appreciated.

Thanks Habshockeyfan! Potassium never even dawned on me! One more reason I love this forum!

Thanks! I will make sure she runs those too. I think I may be a smidge dehydrated too contributing to the fatigue. I have woken up the last few mornings just feeling bleh, medicine type head,and super dry mouth. Urine has been extremely yellow too. I am upping the water content today so that may help.