IM GOING CRAZY

Hello ladies I've been struggling with this period thing .... So as of today I'm 7 days late on my period I've too 3 test days apart and they all was negative I was due to ovulate on the 18th of DECEMBER....TMI I had intercourse on the 14th of Dec and on the 24th of Dec so my question is could I be pregnant or I'm just not getting my period this month because in the past when I took test for my other 3 kids it should show up positive by now so I'm confused and my periods are very regular