I Removed My IUCD On The 9th August, My Last

I removed my IUCD on the 9th August, my last menstrual period was 28th July and I am yet to see my period for this month. All pregnancy test conducted read Negative . I visited my doctor who advised on a serum PT test which also came out negative, he advised I repeat the test in 2weeks. Though I have been intimate since I removed it. I noticed some Crampy feelings on the 24th July in my lower abdomen and it was there thru to 29th July. On the 28th July, it developed to pains in my lower abdomen which stopped naturally on the 29th but I am yet to see am period also despite that. Am seriously worried.