Could this be early sign of pregnancy? Help!

Ladies my husband and I been trying to have a baby for 2 1/2 years now and I started ovulating on March 3rd but yesterday I started to get cramping it more on my left middle side of my abdomin and today it's more constant but mild but sometimes if more sharp and having alittle bit of lower back pain. I'm not due for my period till the 18th so could I have this early of symptoms? 
Please help!!!