Should i be worried?

Ok so my period showed up on the 21st and it ended on the 23rd with spotting and then yesterday it was completely gone my periods always last 6 days idk whats going on im just asking if there is anyone that can give me a little advice on what could be wrong i have cyst on my right ovary its the size of a half dollar my doctor didnt say anything about it effecting my periods so idk what to think any advice or opinions would be greatly appreciated thank you