Cramping and lower back pain

I've had lower back pain for 2 days now and woke up this morning with cramping. Seen the doctor on the 29th of last month and said everything looked good and there was an egg there ready to jump ship and if I was going to have my period it should have started any day. Well no period and my last pregnancy I had the same symptoms. I can only pray on the 18th I have really good news