What Causes Delayed Periods And Prolonged Bleeding?

Sir / Madam, I used to have correct mensulation period (within 30days) & normal flow till my age of 40 years. a year back, i got irregularity and i got periods after two and half months and the flow was not arrested till 10 days. Hence i approached gynecologist and advised to take menospan for 3 days. Then the flow was arrested and then flow started after 2 days. Hence Dr suggested to take meprate for 20 days. Then i got periods normally and arrested. This procedure was continued for 3 months and then i stopped meprate and periods was regularized for a year. Then problem started again dr gave meprate. But i forget one day to take medicine and hence i got periods after 2 days even i continued the medicine meprate. I consulted the physician and she advised to stop meprate and to take Novex DS. I got severe bleeding and adviced to take menospan to arrest bleeding. 3 months i didnot get periods then started with heavy flow. then i was adviced to take scan and found that the endometrium thickness was 17mm and i underwent Hysterscopy & DNC. The biopsy result was cystoglandular hyper placia endometrium and i am taking tablet endace 40 for 20 days. Now my doctor says my endometrium thickness becomes 21mm. your suggestion please.