Thanks for your query.
1. Presence of Cystic hyperechoic structure in the ovary indicates the presence of a cyst (fluid filled cavity) in the ovary, most probably a Dermoid cyst
, which seems to be the main cause for your symptoms of irregular menstruation
2. The pregnancy test may give a false positive result there is an increase in the level of HCG hormone.
3. The confirmatory test for detection of pregnancy is the trans-vaginal ultrasound
scan. It can detect the presence of gestational sac
as early as 29 to 35 days of gestation.
And as you are having amenorrhea since 2 mths, the ultrasound report can be accepted.
Based on the above mentioned facts, it can be assumed that you are not pregnant & the symptoms of irregular menstrual cycle can be due to the ovarian cyst
(most probably a Dermoid cyst) which is producing the hormones resulting in false positive pregnancy test.
So, kindly consult a Gynecologist & get a proper clinical examination done.
Further management might involve Hormonal therapy or surgical removal of the cyst.
Wishing you a good health.