Light periods or something wrong.

I have a 28-30 days cycle. my periods started from 7th April in the night to 10th april, and a little spotting on 11th April. Had sex using condom on 11th April. didn't use any emergency pills. Then on 29th April some bleeding started, it continued till 2nd may , the bleeding was light as compared to my regular periods and the flow was also different, i filled 2-3 pads in these days. To confirm that it was my periods I took UPT on 10th of May and it was negative. But i am feeling very fatigue and I go to the toilet a lot , and my nipples are uncomfortable to touch , so I took a Beta-HCG test , it's value was = 0.45 mIU/ml. What is the problem with my body please help, why am I feeling so fatigue and urinating so frequently. I have attached my Beta HCG report.