Freaking out

So my husband and I have been TTC for 6 years. I recently had a transvaginal ultrasound to see why I'm not having normal periods. Well the doc called and said I have to redo the test. They found a cyst on my ovary that's 5cm! She said because I'm on my period now it may be because of that however if it t doesn't shrink in size after my period (I will hav another ultrasound done some time after) then they will have to do surgery to have it removed. I'm terrified of this. :(