Help!

For the past week or so when ever is it down I feel like something is pushing on my overvies/uterus area. What could this be? I don't have any STD's and I haven't had my period since October 10-19 but I've taken hpt and they where BFN :( is it still to early to test or do you think my HCG level is to low ?? Idk what's goin on. My belly feels bloated more than usual and and the very tips of my nips are really sensitive but other than that nothin. What do you guys think??