2 Periods every month

I am 22 years old. I have a 8 month old son.

Ever since I had my son I have been having 2 periods every month.

Is this normal?

Anybody else have this problem?

Please no rude comments.

I dont think it's any STDs or anything because I am married and I haven't cheated on him.

Every time my husband and I get intimate I spot after.

I am on the nexplanon