SO I took yaz for a year then I switched to Loestrin 24 Fe last m...

SO I took yaz for a year then I switched to Loestrin 24 Fe last month and the period following I got my period a day earlier than usual and It was heavy the first day then it went lighter until Monday it was hardly there. It was about 3-4 days of a period and I'm worried i might be pregnant. On yaz I had 3 days of heavy period and 1 day of light. two months ago I had sex Two days before my period Obviously i was on the pill and had periods since. There is no fatigue or frequent urination or sickness and I have had at least 6 negative Home tests over this period of two months. I'm worried a little, There was no coming inside and he did not wear a condom and he had urinated before sex. I am wondering If it is the pill switch that is tripping up my period or is it pregnancy? I'm so stressed and yesterday a rash developed on my face. not red, ichy or burning just little bumps. I'm worried this might the pill or signs of pregnancy. HELP!