no appetite and diarrhea

Ok so a little bit of background (sorry this may be tmi) but normally I poop I'd say twice a week. I get diarrhea frequently though too. That's just always been pretty normal for me, I've never thought anything of it until others have told me they go once a day or every me, that is abnormal. Lately, however, I have had like zero appetite and have been only eating one meal a day (yes I know that isn't good to do but I just haven't been hungry at all) I am a bigger girl so I usually have too much of an appetite but lately like I said it's been almost non existent. When I DO eat, I get diarrhea almost immediately to a couple hours later. Has anyone else ever experienced this and know what may be going on? Should I be making a doctors appointment or just wait and see? any suggestions?