Apparently my girlfriend's period is a week a late, We last had sex on valentines day and I wore a condom, she doesn't take birth control though and that's a problem.

I had her take a pregnancy test yesterday and it was negative. She has been having period symptoms like short cramps and her breasts are sore, but no bleeding. Apparently Breasts can be sore after three weeks of pregnancy, and valentines day was about three weeks ago. On the box of the pregnancy test box though that it detects pregnancy after 6 days and its been more than 6 days.

I'm still a little worried and my question is could she be pregnant and could the pregnancy test be wrong? Or does this kind of thing happen? She says it's happened before where her period skipped two weeks, and I remember her period started early once. She has been running a lot and I read that exercise can delay a period. Can these factor into her period delay? I also pulled out.

Well being an 18 year old girl I could probably be some help on your forum lol. Im a runner. 3 miles a day. Her period will be late, short, light and every she mightn't get it especially if she just started running. She will still get period symptoms. Her boobs are probably sore early because of the dramatic weight loss that running does to you and boobs will hurt if their getting bigger or smaller. She's also young so her periods are still trying to regulate. As for not being on birth control get on it. Good thing you use condoms but be extra safe and tell her to get the pill or something. If she's 18 she doesn't need her parents permission and family planning is always free. For that piece of mind though if you want you can take a test in another week or two and see what happens just because I know when your young and sexually active that's one concern that sits on your mind.

She took another test today, I kind of had to make her(don't ask, she was being ridiculous) and it was negative again
We are 98 percent sure we are in the clear, but you never know, I am very un-lucky
I'm mostly concerned with getting her on birth control, I'm pretty much taking all the responsibility and when it really comes down to it I'm the only one protected, she's not.