Advice needed ASAP

So I have a two children. My son was born February 10, 2017 and I have a daughter that was born February 23, 2018.

After I had my daughter I started birth control and used it up until this last month. My periods have never been late, unless I was pregnant. Then I’d test and have a positive right away... well this month, my period hasn’t came and I’ve taken tests and they’re all negative so I’m at a total loss of what to do..

Do I go to the dr or keep waiting....

Like my husband and I haven’t tried preventing getting pregnant again... like if it happens, then it happens.. we’re both pretty open to the idea..