I just started taking birth control pills for the first time on 10/20/09. I had unprotected sex right before and during my last period (10/16/09). Now I think I have pregnancy symptoms, I haven't missed my period yet but I'm tired all the time but have a hard time going to sleep and staying asleep, my breasts are tender, I have cramps, gas, slight bloating, back ache, a mild headache, I get dizzy if I stand up to quick, and I'm nauseated. Is this from the pill or could I be pregnant? 

Hey Mandy.

Boy it seems there are a lot of lurkers on this forum (782 views!) but not many posters? That's too bad.

I know quite a bit about conception as I started reading many books this past year as we've been Trying to Conceive since August etc. And, in my opinion, it seems rather unlikely that you are pregnant if you only had sex before and during your last period. By BEFORE how many days before do you mean?  If it was 2 weeks before then yes, you could be pregnant. If it was a couple days, odds are very very low.

I think you are most-likely experiencing birth control pill symptoms/side effects. They change your hormones in a similar way that being pregnant does. So, you can have some of the same symptoms as pregnancy. I sure had a lot of different ones from the different pills I had been on when I was younger. Breast tenderness and cramps etc. still happens for many women while on the pill.

Was your last period any different than normal?

So, if you really only had sex before and during your last period there's barely any chance of you being pregnant. I would definitely not have unprotected sex right now though as I think you should wait a month for the birth control pills to fully kick in. 

Hope that helps.