Mid-cycle bleeding, missed period, negative result PT

Patient: Hi,I had my last menstration on 18 June 2015 and ended on 20 June 2015.My husband and I had unprotected sex twice, the first was after few days after my period and the other time was on 1 July 2015.on 2 July 2015 night, I had mid-cycle bleeding until 5 July 2015.I was supposed to have my next menstration period on 19 July 2015 but no signs of having my period.On 22 July 2015, I did a pregnancy test but it was NEGATIVE.today, 30 July 2015, I had a spotting again.I haven’t tried to test again. Could you let me know what is possibly happening to me?I’m planning to do a preganancy test tomorrow morning.Thanks

Symptoms: Big breast, always sleepy and tired, always hungry