Thouts on this?

My ovulation date was March 13, 2017 my partner and I had unprotected sex that day. Today is my 7 DPO and I am experiencing constant backaches, and cramping. I feel the cramping more when I sit up, also for the past three days May 18, 2017, May 19, 2017, and May 20, 2017 (today) I am experiencing stomach aches and constipation. I am a small girl my weight is 112 and I'm five four. For the past 3 months since my miscarriage my period has always came on the 29th of each month. Only thing I can remember is having a sharp pain for a few seconds sometime a few days (maybe 2 days after ovulation) that I was able to relate towards my implantion pain last pregnancy (ended in a miscarriage) so is the signs I'm having now possible signs of pregnancy? I also had creamy white discharge but nothing like my nornal discharge.