af is late

My af is late I've had no sign of my period at all I had a miscarriage in February 2016 and been trying again since I've took several tests but got nothing I don't know what to do I had a bit of spotting few weeks ago and a couple of cramps that lasted 5 seconds and nothing since I'm going out my mind as I'm never late for my period the last time I was I found out I was pregnant need some advice and help please