Missed period + unprotected sex = pregnant??

Ok so i dont know where to start.
So for me i have REGULAR PERIODS.for example:if i start october 25th ten november i would start the 25th of november.anyways November17th me and my boyfriend had unprotected sex.We had sex atleast 4 or 5 times that day probably.Then Sunday the 18th we had sex twice unprotected also.Then that monday the 19th we had sex once unprotected,then tuesday the 20th we had sex once,then wednesday we didnt do anythang. then Thanksgiving thursday we had unprotected sex,then friday night we had unprotected sex,then early saturday mornin we had unprotected sex.then we didnt have sex all the next week.then yesterday we had sex once and it wuz unprotected sex.
ANYWAYS like i said my periods are REGULAR.The last time i started my period was October 25th or 26th.Well i missed last months period.i was suppost to start my period the 25th or the 26th of November which is really recent.I TOTALLY MISSED NOVEMBER25 or 26th's period.I never in my life have ever missed a period or been late.of course i did here that if you have sex for the first time it could mess up ur period schedule is that true??because if so November 17th was my first time having sex.i saved my virginity for my boyfriend i have now.all them other guys i dated wanted to f**** me but i wudnt let them.but i am happy i lost to him cuz he wuz a virgin too.but anyways off dat subject...so is it true that if u have sex for the first time it messes up ur period schedule??anyways my boyfriend bought 8 preg test.half of them were digital preg test and then the others were the ones that just come up wit the lines.if ya know what i mean.anyways the pregnacy test come up wit the lines all came out NEGATIVE.of course it only been a week or wateva.but one day last week i came home from school and took a digital preg test and it came out positive.so iunno if im preg or not.and after i had sex wit my boyfriend couple days later i started to cramp up.its been like 2 weeks now from day one when he and i had unprotected sex which was november17th. anyways lately i been having lower back pain and since last saturday the 24th i havent been able to lay on my stomach cuz it feels weird and it would hurt. and lately i have been really tired. and i been sleepin in some of my classes and i never do that.and i been eatin alot lately.and cramps off and on.and i feel like im fat which i guess is fatigue.but anyways and i am just now gettin rid of my cold i have all i have now is a really really runny nose.
but anyways like i said i missed my period i wus suppost to start november 25th or 26th and well i was a week and a day late til today.
i went to the bathroom and i wiped and it was all brown and nasty and then it looked a lil bloody and mucusey.*SORRY TO MUCH INFO*
but anyways iunno if i started my period or not, as many as times me and my boyfriend used unprotected sex i should be pregnant. iunno its weird. i mean its like i started my period or somethin.its not heavy or anythang. of course im never heavy when i have a period. but like i said i have never in my life started late or missed a period.
Does anyone know if i could be pregnant??if so i will be so anxcious because i always wanted a baby especailly wit the guy im wit right now. i know he will be a good daddy. but iunno if i could be pregnant or not. oh and i also have been have lil headaches off n' on.
but since the first time we had sex which was Novemer 17th it has been 15 days...which is 2 weeks and 1 day.so iunno could i be pregnant or not. people say i need to go to doctor or to a clinic to see if im preg there or not.but i dont know how i can do that. i mean i can drive n everythang but its just i dont want my mom to find out yet.and i dont know how im gonna be able to get there because i go to skewl every week except the weekends so iunno....unless i can get a friend to take me on a saturday to a clinic or something but iunno....like i said a million times could i be pregnant or not??