Had protected sex in march, but periods.

Had protected sex in march, but periods didn't came on expected date in march, waited for a month and in last week of April i did many home pregnancy test and all were negative and then i visited to a dr. He gave me some pills to take that twice daily for 5 days and after periods came in the first week of may and i also did a ultrasound and it shows a medium size cyst in my ovary after 5 days of periods end Doctor prescribed me a ginette35(21 days course) after consuming this medicine periods came after a week like around 6th june and after full 5 days periods i got my periods again in a week, on 17th june for 5 days, and yesterday i had light spotting of brown and red colour and today, from early morning i started bleeding again. Can any doctor please help me to understand what is happening with me ? Is this cyst or any other problem i have ? Please give answers as soon as possible, Thanks