Both USG of your uterus
shows that endometrium has some complex Echo texture,increased endometrial thickness, continuous bleeding and your age ( perimenopausal) suggest that you must go for Dilatation and curettage
for your endometrium followed by hist-pathological examination of the sample. it is important to rule out any endometrial abnormalities. Histopathology will rule out any pre-cancerous or cancerous changes in endometrium. It could be just hormonal
disturbances which are common during this age, but better to rule out other endometrial abnormality. D& C will not only help in diagnosis, but it will stop your bleeding also.
could just be a co-incidental findings, but again it is better to rule out the above said abnormalities.Though in second USG, there is no myometrial cyst.
Nabothian cysts are not responsible for bleeding, but shows chronic infection of endocervical glands. It may or may not require any treatment depending on related symptoms like excessive vaginal discharge
better to be safe, prevent, and diagnose early .
Difference in size of uterus in both usg, could be due to subjective errors.