I’m confused...

I had sex on March 1 and he withdrew. I used plan b because it was within my fertile range. I had unprotected sex again during that cycle but he didn’t cum in me. The week after, I experienced spotting a week earlier than my period would normally come. I figured it was the plan b. I took a pregnancy test a couple days ago, it was digital and came out inconclusive. I haven’t gotten another period yet and I don’t think the spotting was an actual period. There were no clots and it was medium to light amount. Could I be pregnant?