OK, here's the deal. I had sex twice August 23rd and when i was getting my boyfriend off the second time (he did not ejaculate the second time and urinated in between the first and second) the condom lifted and fell off (it was lying beside his penis). i don't think it was ever inside me while not on him (if it was it was just the very tip), but i cant be positive. Some extra information is it was a new condom that didn't break (i filled it with water to make sure) and i was on my period (about the 3rd day of a 6 day cycle).

Now i have an irregular period so i can't even check if i'm late but i shouldn't even be expecting anything for at least another 13 days (that would make it exactly a month from my last). My concerns are if i'm pregnant (not on BC). i have a few symptoms but alot of sites said that pregnancy symptoms can also be brought on by stress, and i am very stressed right now for many reasons. Firstly the whole pregnancy concern and i'm also on my first week of college. the symptoms i have are:

-headaches (but those are not uncommon with me)
-my breasts are not sore (but they seem slightly more veiny than usual)
-i'm kinda nauseous (but that's mainly only when i don't eat for a few hours or if i eat when i first wake up)
-i'm usually always tired (but lately it just seems like i'm really tired)
-i have a few pimples starting out (but its been really hot here so it could just be environment related. plus im a teenager so pimples are normal)

God i know i'm freaking myself out but i'm really worried. getting pregnant is the last thing i need right now. i guess what im asking is just some advice or just your opinion on whether or not i have anything to worry about....and also when is the earliest i can take a test with an irregular period and get accurate results.

sorry it's so long