Weird periods

I started on a new pill in February. My period came late that month. Then had my period March 21-30. It was very abnormal. My periods usually only last about 4 days. I went and got my pill changed in April due to thinking it was the pill I was on. Then my period was April 18-27. Again abnormal. It is now June 1st and i have not had my period. Not sure if I should be worried.