strange cramping sensation in my lower stomach

Hi! I'm stightly impatient and confused, I'm nor due my period for another 2weeks, and know that I would have been at my most fertile at the weekend, although I'm taking the microgynon pill but have missed 2 tablets and took the 3rd late!! The past 3days I have had a strange cramping sensation in my lower stomach with occasional shooting pains, not painful just slightly uncomfortable, iv been very emotional crying at the slightest thing, slight lower back pain and soooo tired but difficulty sleeping, I also has slight clear mucus yesterday which is unusual for me and constant headaches for 4 days now. Iv stopped talking the pill altogether now just incase and obviously it would be far too early to take a test! Can anyone relate? Or give advise please :-)