I am a sixteen year old girl who recently had sex with one of my friends for the first time.. It wasn't something I wanted to do or felt ready to do but it just kind of happened and I am pretty upset about it as it is.. But to make matters worse I'm worrying myself into thinking I might be pregnant because I'm getting weird stomach pains in the morning.. The sex happened a week and a half ago, he used a condom but did ejaculate inside me.. I got my period two days later which is usually a sign that you're not pregnant but I'm still scared to death..
Go to your doctor and ask for a test to se rig you may or may not be able to have children and the doctors will be the best people to ask for advice
You say "he used a condom but did ejaculate inside me". If his semen was all contained in the condom, you should be OK. The fact you have had a period would indicate that you are not pregnant (although not proof), but also, if the period was on time then you would not have likely been fertile two days before that period started.
Having had sex once (was that when you lost your virginity?) , it will be more difficult to resist again. Sexual intercourse is a bonding activity.