Cyst in left ovary. Please suggest me!

Hi I am 29 yr old unmarried female. A few days back I had a severe pain in the area below os my waist line it is similar to period pain but the pain was quite sharp n unbearable. Immediately I went to hospital where the doc suggested me for USG. The result shows cyst in my left ovary after seeing the result doc gave me medicine named as dinomac and she asked the period will no come inbtw of 2 months course of this medicine n the cyst will wash off by maintaining the hormonal balance. So here I am really scared that I got my period on 15th august n again it came back on 28th August (medicine started taking after 28th August) As if I m going through my research the medicine is to cure endometriosis so how cyst n endometriosis is related n how this medicine will cure if my period cycle get effected due to this tablet. Please suggest me