Does Back Pain, Delayed Period And Increased Appetite Indicate Pregnancy?

I have middle back pains for the pass week around the same time I'm supposed to get my period which I haven't. My lower tummy been feeling more swishy kind of a feeling & more hungry. Today I had alittle white discharge. What percent that I could be pregnant? Or what else could be wrong my back hurts to the point it's even hard to sit up & it started out of no where on Monday.