Missed Period, Negative Test

I was supposed to have my period last Wednesday, it never came. So this morning, I took a test and it was negative. But, I still don't have my period. I've never missed a period before, however, I did get my IUD taken out on June 13th and bled for about five days. I've had unprotected sex with the same guy quite a few times over the last month. We had sex on June 8th, then again on the 23rd, then again on July 9th. We slept together multiple times on each date. I randomly had some brown discharge on Saturday, about four days after my missed period which I have heard can be implantation bleeding. I'm too scared to tell my parents what's going on. What should I do?