Just recently I started having unprotected sex with my boyfriend.  Here is my schedule as is follows:

February 14 - First time we had unprotected sex AND period came that same night
February 17 - Period ends
March 13 - Period begins
March 16  - Period ends

February 14th was the first time we had ever had unprotected sex, prior to that it was always with a condom (that never broke), and I have been on birth control for over a year and am still taking it.  

My concern is that since then I have noticed a slight fat ridge developing just above my pant-line or where my jeans start.  It's squishy and I can pull it a little, but otherwise isn't a lot.  My weight has not changed this past month, I am between 93-100 pounds at most.  I began checking my weight more often after I noticed the fat bump I had, because I am afraid I may have gotten pregnant somehow.

I do not know much about medical facts, but is it possible for me to have gotten pregnant and still have my periods come on time?  Is the fat I notice just my paranoia?

I have noticed progressively, months prior to our first unprotected sexual experience, that I have been developing a stomach of sorts.  Possibly due to sitting down a lot.  Now I am getting scared because if there is a way for me to get pregnant and still have my periods come on time then i will be in my second month and I will want to get an abortion before it is too late.  

I have known some woman to have gotten pregnant and not really show it at all, other than developing a  tiny bump of fat that can be disregarded very easily, so I am afraid that my be my situation as well.  i have also read some pages online about how it is possible to get your period even while pregnant.

my periods are full on periods, starting off light and then getting heavier before ending.  I still have cramps, discharge, nothing seems out of the norm except this strange lump of fat I have.

If at all possible, besides providing an answer, would there be a way for re-pliers to provide me links to more information about distinguishing whether i am pregnant or not?

THANK YOU VERY MUCH FOR RESPONDING IF YOU DO