PLEASE help! am i pregnant?

My boyfriend and I had unprotected sex 2-3 weeks ago, and we used the pull out method. About 3 to 5 days ago, my breasts became really sore... more than when i get my period. i should have been on my period this month from either 20th-30th. i should have started on one of those days. i never keep track of my period, and my period is usually irregular. i have been stressed and worried a lot. all i have felt is sore breasts and my stomach kinda hurts. that's it. please no mean comments, i really need your help. please. i am 17 years old. oh and if this helps, i had to go to the hospital nearly 2 months ago because i had an ovarian cyst that ruptured. my doctor wants to put me on birth control due to my irregular period. i have not seen my doctor for over a month. please help me.