Feel like I’m going crazy- on BC/bleed but pregnancy symptoms??

So I’ve been on BC pill for a few months since having my second baby. I’m good about taking it 99% of the time, very rarely miss or am late. I’ve been having a withdrawal bleed, but it’s not as heavy as what’s normal for me (though still red blood). I took a test and got a super faint/maybe line right at the end of the time window but it wasn’t really clear enough to say positive... also been having headaches, feeling lightheaded and occasionally slightly nauseous, which is not normal for me on BC. Feel like I’m going crazy! Has anyone had similar experiences, is it possible to be pregnant? Or am I just having weird side effects this month. 😬