Could I be pregnant?

Okay so I'm 18 days late, which I'm rarely late and when I am its only by a few days. I've been more stressed than usual the past few weeks, but I'm not now. I'm having lower back pain, my boobs feel heavy, some nausea, headaches and some milky vaginal discharge. I've taken 2 pregnancy tests about a week and a half ago and they both came out negative. Do you think I could still be pregnant and go see a doctor? ( I'm terrified of needles, so the idea of a blood test freaks me out). Or should I wait it out and see if my period comes? If I'm not pregnant, I don't know what else it could be?