Negative hcg, chances of pregnancy?

Hello doctor, i had protected intercourse on 16th August, i was a bit scared so i took an ipill, i again had protected sexual intercourse on 29th too but I didn't take any pill as it was completely protected, my LMP was 9th August. I suffer from pcod so my cycle sometimes is irregular, however lately it's been 30-31 days since a few months. I was supposed to get my periods on 7th of September however instead of period flow, i had brown and red spotting from 7th for 4 days, very light. I did few home pregnancy test all were negative on the 35th day of my cycle i went for beta hcg which was negative too, I wanted to know if this is because of hormonal imbalance or am I pregnant? I'm having uneasy feeling in my stomach, occasionally back and leg pain, is the ipill causing a hormonal imbalance? It's my 38th of cycle. Should I repeat the beta hcg test again? Or is it accurate that no pregnancy? Any medicine I can take to get periods? Pls help really worried