Stopped birth control, late period, and negative pregnancy test

So last month I started birth control after my previous period but after two weeks it made me feel so horrible I stopped.

After I stopped, my period did come on it’s normal day, but it was heavier than usual and longer than usual and I had no cramps.

Now a month later my period is 4 days late, but I’m feeling slight cramps and bathroom issues. Thinking I might be pregnant I went and bought a pregnancy test which came back negative.

The last time I had sex was Jan 1st, if anything I would be 3-4weeks.

What are the chances I’m pregnant?