Got my periods in 20 days. Sex.

I have a history of ovarian cyst, it was 2 years ago. My last 8 cycles were normal and range between 21 to 25 days. Whenever I had any issues (during cyst)...my periods were always late they never came early. Last week my and my husband had unprotected sex (he ejaculated in me) And after 3 days I started bleeding. It was the same week as my supposedly ovulation week. My last periods was on 31st December. At first day it was light, pink, Mixed with transparent flow. But later that day it started bleeding heavy, like periods. It's my day 4 today and seems like I had my periods early. I wanted to know why this might have happened as my got my periods in 19 days Also if my periods were triggered with the unprotected sex can this be a sign that I might have problems conceiving No unusually heavy bleeding. Lower abdomen Light to moderate cramps (I never have crams during my normal periods) Irregular flow (I need to change pads regularly but not my usual flow) 1st time unprotected sex.