I am now 6 days late for my period which is more than I have ever been before.

I am 19.

My boyfriend and I always have protected sex and check the condom every time but I'm really starting to freak out.

We've had sex A LOT this month and last month after my period. We haven't had sex since last Sunday. I've been having lower back aches and last night I seriously thought I would get myperiod because I had cramps and a lower back ache but still nothing. I had some brown spotting earlier this month and I thought I was getting my period so I put in a tampon but after that there was nothing. I had very very little brown spotting a few days ago but nothing red. I have taken 3 home pregnancy tests and all have clearly been negative ( I did one first thing in the morning). My breasts are a bit sore now and then but nothing ridiculous. I am a college freshman in my first semester so I do have a lot of stress and my diet has been really bad lately. I'm not eating right at all compared to how I used to but I do exercise almost everyday. Could I actually be pregnant? I am incredibly worried.