bloopy's Trying To Conceive Wish

My boyfriend and I have been trying to have another baby when I got off the IUD. My periods has been irregular & they are hard to track. Every month since sept we have bought preg test to comfirm our pregnacy & they have all been neg.I came on in nov for two days and im late again,so I went out an bought another test well Im cramping and spottin now. To make matters worse everyone around me is preg, except me. I'am so confused and we are getting tired of trying please give us hope.