Help? 9 days late!?!?!

My husband of 3 years and I have been trying to conceive for 4 months now for our first baby. I had the mirena removed in September because I was bleeding constantly for 3 years while I had it. I have had regular periods every 28-30 days since having the mirena removed. AF usually lasts about 6 days. I am now 9 days late with AF but all I keep getting are BFN's. I tried different brands and testing different times of day. I have had cramps and back pain for the last 2 weeks and only one day of really light spotting. What do you think this is? Can someone just skip a month like this!?! What do I do now? I don't want to be that crazy girl calling the obgyn for everything. I'm ok with me not being pregnant as long as AF comes to I can try again this month!