Change of pants today

I am conflicted about how I feel about this. I tried on a pair of black pants before I came into work today, which have always been a little tight. It's a junior size 4. I decided today that in my profession, I don't need to be wearing tighter black pants. I than pulled out a pair of these awesome Black & White pants I got awhile back, still a size 4 but more room for my booty. I am totally conflicted on how I feel about this. On one hand, I work out 6 times a week and total watch my food intake, so it's mildly frustrating that I seem to be gaining, although I want to tell myself that it is partially muscle gain from badass yoga and Jillian. I'm not by any means heavy or looking like I gained the 15lbs (thanks IUD) I have. People keep telling me that last year at 5'7" and 125lbs I was WAY to skinny (which no one told me till now) and that I "wear the weight well" . I am NEVER sure how to take this. I think it all depends on the day. I don't know.. I go back and forth. We have a vacation coming up, which involves sun & bikinis. I have been busting my ass to be toned for this trip and I am hoping the photos will show it. I am still a size 4. While my pants may fit a little tighter, everyone keeps me how much better I look. So I just think of how I watch my diet, workout like a fiend & try my best to keep on top of it. Other than that, WTF am I suppose to do?!?!?

Oh and side note. To those of you who watched SuperSize Me (which for me personally is the reason why I stopped going to McDonalds) you will recognize this man. 25,000th Big Mac