Can being pregnant with twins make your pregnancy test go from faint (but noticeably positive) to a straight negative?

Ive gotten a few tests that are faint positive but noticeably positive.. I tested the day I believe I was supposed to get my period . Jan 29th was my last period.

I tested today negative.. on feb 29th I didnt test but the day before I did and I noticed my line got darker..

I have no signs of af .. and once I think of it I think I had very very light implantation "spotting".. could I be pregnant with twins? Its just its odd that Im gettin bfps before. My line progressed. I feel pregnant .. the one day later after no testing .. a big negative! .. I dont trust it .. even last month when I had a chemical pregnancy I had a faint bfp while af was on.. I have noo sign of af.. just the feeling of being "wet" down there like I had with one of my pregnancies. And I dont remember it being this much.. ill ve scheduling a doctors appointment today .. id just like to hear stories or what u may think..