I Recently Was Due For My Period Sunday And Did

I recently was due for my period Sunday and did not get it. I am in Junel fe 28 day, and I missed the first pill in my pack, so I took two pills the following day. However I had unprotected sex that day. For the last week I've felt nauseous, bloating, swollen breasts with large blue veins and sore and very tired. Today I had a stringy clear like discharge with blood in it but then it stopped. I took a pregnancy test the day of my missed period and this morning and both were negative. Could I be pregnant?