Never got my period

So I’m trying to get pregnant and me and my boyfriend have been having unprotected sex. I have been waiting to see if I get my period but it’s almost the end of the month and this is the third week that I haven’t had it. I’ve been feeling sick in the morning but never throw up. My nipples feel soar some days but others it won’t. I pee two or three times in a hour and I feel like I’ve gained a little weight but I took a home pregnancy test and it was negative. Can I stress enough not to get my period for a while month when tho I haven’t really been stressing?