I look pregnant, but i dont know.

I will try to make this short. I live with my boyfriend of a year and a half. I am currently on birth control (Cambrese, which is a pill that allows me to only get my period every 3 months) and have been on the pill since I was 17. All that being said, we do have unprotected sex. Now, I used to be a very stick-thin girl. I grew up having an extremely fast metabolism. I could eat anything I wanted, and never gain a pound. I am 5'4 and have never weighed more than 95 lbs. Getting to the real point, over the past couple of months, I have started to gain a lot of weight. I went from a size 0 to a size 5 in the matter of like 2 months. I now weight close to 115 lbs. I eat double the amount I used to, and barely feel full, and i am ALWAYS hungry. When I am standing, when i have a shirt on, i just look like I have a little pudge bump. however, when I look with no shirt on, the pump is very prominent and defintiely looks like a pregnant belly, and feels somewhat hard. But, when I sit down, it will either hold it's round shape, but 90% of the time, it will just look like squishy flab. I never experienced any typical symptoms. I mean, for a couple of weeks I would randomly get a wave of extreme queasiness throughout the day, but never any actual sickness happened. I do have bad cramps sometimes and some slight lower back pain, but nothing I really consider alarming. Not to be gross, but I always just assumed it was normal gas. My breasts and butt have most definitely gotten larger, as I have always been a very "small" (aka flat) girl, and my breasts sometimes feel tender, but I always assumed that was all because of the weight I have gained. I know that when you get older, your metabolism can slow down, but this was so rapid, it shocked me. And, as I said earlier, I have been taking birth control pills since I was 17. I am now 23. So I have been on the pill for 6 years, and a couple of weeks ago I noticed I had some kind of heavy spotting, that appeared to be almost like the start of my period, but would then stop after a couple of days. I shouldn't still be having that, as I am nowhere near new to the pill I am on and I am not due for my period for another month. I know people will say "well, take a pregnancy test"...and I have debated it, but if it comes out negative, I don't want to run the risk of a pregnancy scare with my boyfriend should he see it. And it's hard to gauge if I could have missed a period, since I only get one once every 3 months. I do have an annual check-up with my OBGYN next week, but I am too nervous to really wait until then to ask these questions. That's why I what to see what you all think, especially those who may have had similar situations. I have been taking my pill daily, and I do have the occasional beer or glass of wine, but I am starting to get nervous that if there is a possiblility of a pregnancy, I may be harming the baby. But then again, it could be just that I am under a lot of stress with work and everything so I suddenly gained weight and my metabolism caught up to me and I am just paranoid. What do you guys think? Any ideas or advice??? Thank you!