Missed period,Cramping and pulling sensation in uterus?


Hey all,I am on clomid 100mg 3rd round..I am irregular only but clomid helps to make it regular..I got my period last two months on cd 28 correctly.

But this month today is CD 36..but I didn't get my period yet..I had sore boobs two weeks back I thought I am getting my period..but it has gone..no period at all

I am having cramping comes and goes for almost 2 weeks...from yesterday itself I am having strange feeling like pulling sensation on my uterus..

I took a test on CD 32..but it came up negative..I don't want to get another negative..so I didn't take a test till now..plz help..