Sick/nautious feeling, weight gain, constantly going to the bathroom. What is wrong with me?

I just had my period 20 days ago. I have been off the pill only about a month and a half. I feel dizzy/nautious lately. I don't know what is going on. My stomach is getting bigger and bigger it seems. I have been looking online for answers coming anywhere from being pregnant to possible diabetes, and some have said it's an ear problem, because I do feel off balance. Almost disoriented also at times. Nothing real bad though. I just want to know if I go to the doctor, should I call the OBgyn, an ear nose & throat specialist, or some docter that knows about diabetes. Sorry if this doesn't make any sense, I just don't feel very well.