Period 92 days late. Help me.

My last period was 120 days ago. I'm 92 days late. I've taken 6 hpt tests and all have been negative except one this month. When I tested later it was back to negative. I even had a blood test done over a month ago and it was negative as well. I've felt pms symptoms for a couple weeks but my period never comes and they're more severe. When having sex with my fiance whenever it's pms it feels a bit tender at first. However for the last week or so it actually hurts if he moves like normal. I also feel a lot more pressure up by my cervix as well. I'm not sure what's going on. I thought I was pregnant because after my last period we were having unprotected sex every day sometimes more than once until mid November. My last period was October 2nd. However with all the negative tests I'm doubting I'm pregnant. Has anyone else experienced anything like this? Friends have told me about some stories where women were pregnant but didn't get a positive test for months. Could I still be pregnant? Or is it something more serious?