Could I be psyching myself out or am I pregnant?

Although my boyfriend and I aren't actively TTC, it wouldn't be a bad thing either way but lately I've just had a funny feeling (not the "I feel pregnant feeling" though.) I have been on the pill for about 2 years now but I know that that's not always 100% effective. I take it everynight at the same time within an hour or so sometimes and if I do miss it (rarely) I take it as soon as I remember. For the past 2 weeks I've had the "funny feeling", very tender nipples, my sense of smell has majorly changed (I love Pepsi but I can't even stand the smell of an empty can that is sitting beside me,) I'm up 3-6 times a night to pee and have the worst time getting comfortable/back to sleep after that and although this might be TMI, I go a couple of days where I'm basically constipated and then a couple of days where I have diarrhea and then the cycle starts again. AF is due on the 21 (tomorrow) and I just can't wait, I'm driving myself nuts!