Pregnancy scare

Arin
So my SO and I have had sex without a condom multiple times. He hasn't cum in me, I know this as I have painful sex problems and we can't do it for that long, he's only had pre. 
Recently tho I've been experiencing constipation and back pain, nausea after exercise, dizziness and sore breasts. My period is due tomorrow and I'm very concerned that  I could be pregnant...?