Plan b prologned symptoms

He has ED and I just got a new high-stress job, plus our daughter is in the throes of toddler tantrumdom, so we haven’t been having a ton of sex at all. So I’ve been off the pill for a bit because I detest what it does symptom-wise. Then on November 2nd, we had a rare steamy encounter, ending in my husband *unleashing the demons* inside of me. I had just ended my period, but ended up taking a plan b on November 5th because I noticed I had a lot of really stretchy discharge. Fast forward to now, and I’ve had serious nausea and heartburn for the past couple days. I feel straight up pregnant, but 1. I don’t think symptoms could start this early (they definitely didn’t with my daughter) and 2. I feel like this is a prolonged side effect of plan b. Can plan b symptoms still linger 2-3 weeks after taking it?