What is going on

So lately I've been really lightheaded and kind of feeling dizzy. I'm wondering if it could be because I recently got my appendix out my periods kind of messed up because I got behind on my birth control and also from my appendix coming out I lost around probably 10 or so pounds I weigh about 105 pounds, I'm 5ft so that was a lot of weight to lose. I found out I have to get my gallbladder out so I'm not eating as much as I should be probably just because my stomach gets upset so easily and I get the gallbladder pains but I'm just wondering what's causing me to feel so lightheaded and dizzy all the time any ideas???