Scared!

Hi, okay, i'm 16 and had sex with my boyfriend about two weeks ago. We had sex 4 nights before I was supposed to get my period. I'm on birth control and he wore a condom. On tuesday, when I usually expect my period, I got it but it was very thick and brown colored, and just abnormal. For the next couple of days it was a very light weird period, not normal at all. Seemed like dried blood more. Then it turned into normal blood but very light and ended a day sooner than it usually does. I was worried so took a home ept pregnancy test. It was the kind where a + shows up if you are pregnant, otherwise it is just a vertical line meaning you are not. The control line showed up just fine, and the normal vertical line showed up, but then on the horizonal line which would mean pregnancy just about about 1/8 of thel ine showed up clearly after a minute but nothing else showed up. Not even a faint line on the rest of it. I was extremely confused about this, so I took another test about 2 hours later with one of the digital ones that say "pregnant" or "not pregnant"... This time it said "not pregnant" but I am still worried becasue it has only been a week since we last had sex. Like I said, I got my period but it was very light and thick and weird. I have another pregnancy test and am going to take it in a week but I am very concerned. Am I just worrying myself too much? We also had sex last month, but I got my period normally that time. Am I just crazy or should I be concerned?

Also last time we had sex I saw my bf wipe precum off of himself before he put the condom on, and so it was probably on his hands and then it could have gotten on the outside of the condom... Not sure if this can happen though...