Irregular periods. Stopping desogestrel?

2 months back in July I went to doctor complaining about heavy periods with clots for about 5 days. However my periods were regular and I was also breastfeeding my 20 month old baby.after the scanning and other tests(sugar and thyroid) doctor told reports are normal and it was because of estrogen slurge.she advised me to stop breastfeeding and gave me desogestrel tablets to take for a month.after which i can continue if needed for birth control. I took all the 28 tablets the first month and and my bleeding became normal. but I took only 16 tablets out of 28 the second month and stopped because of lot of pimples. I stopped the tablet on aug 18 and since then my periods are irregular. I saw a very little bleeding for 8 days from aug 27th and today again I see a little bleeding. is it normal after stopping desogestrel?