Heavy Hairfal occuring since 8months now

Hello Sir/Madam, I have been losing hair drastically since 8months now. Previously i had thick voluminous hair with less hairfall.I usually sleep very late at night and that has been there now for years . I do change places every few months but this was not the case earlier.In june i had taken some medicines to abort pregnancy during which i wad advised by the doctor that i might have side effects.After which i started losing hair but that should have been temporary effect, right? My hairfall doesn't stop and my hair has become too greasy and i think am losing hair mostly at the back of my skull where my left partition ends. I am using organic castor oil since a month now and am taking doctor recommended Vb 7 tablets since few days.I don't think any of these methods are working.Do you think i should give some time or should consult a dermatologist? If you can tell me the reason or medications, i would be grateful.My hair is coloured and i have used no other chemical treatments ever.