How Long Should One Take Diane 35 For Irregular Periods?

hi, I have an irregular period and I didn't have it for 2 months, I saw a dr. she gave me primolut -nor to use for 5 days and she told me to wait 7 days and then use Diane 35 (I have problems with my hair fall) which I did but my period came on the day I started Diane 35 and till now still have it (8 days).
My question: is it normal to have it that long bcz it was late for 2 months?..Thank you