Anybody might help?

3 months postpartum and I EBF so I don’t have my cycle yet. On the 20th of last month I used the pull out method and last night I felt nauseous so I panicked and automatically started thinking that I was pregnant. Today morning I tested and it came back negative but I feel like it’s not accurate. I might just be psychologically making myself crazy. Should I trust that test or by when should I retest?