Uh-Oh Girls...I'm late!

I've been on the pill for 6 months now, so my period is pretty normal by now and I've passed that stage of adjusting to the hormones. Me and my boyfriend have sex a lot (like 2x a week at least) and I take my pill everyday (but not on time cause my Dr said it didn't matter). The thing is, now I'm late??? This never happens. I had spotting a few days ago and I've been moody and constipated all week (with one day of diarrhea). Could I be pregnant? I think it's too early to take a test, though.