Advice ladies please.

I had my sleeping baby 5 weeks ago. And bled for a week after. Felt fine (physically!) and me and my husband had a night of madness/wanting to feel close and had sex twice 2 weeks after. We kind of regretted it because we aren't using protection, because obviously we do want to try again but we were going to wait a cycle first.

I figured out (after sex) that I was probably ovulating them days and on Friday just gone I had dark brown discharge which I have never had before. When I've googled it it sounds like implantation bleed. I never had this with my boy. It was exactly 9 days after sex that I saw the discharge. Today I took a test, a first response one and I think I can see a line, but only when I shine a light on it.

Not sure if I could be pregnant. Any help?