This hardly ever occurs with levlen as it contains both estrogen
Please check if you are using the pills properly. If you are using levlen 21, take one tablet daily for 21 days at the same time and then a tablet free 7 days. If on levlen 28, take active tablets for 21 days and inactive ones for 7 days when you will menstruate. If you take the active pills continuously, it will cause irregular bleeding.
If you are taking the pills properly and if the quantity of blood in periods has decreased, do not worry but if there is no bleeding, get a pregnancy
test and an ultrasound
to rule out any other pathology like an ovarian tumor
Hope you will find this useful. Thanks for the question and have a good day.