Positive and negative test

Hi there!

So my period was around 5 days late (which is not normal) so I took a HPT and it said positive!! My fiancé and I were so excited, as we’ve been trying for almost a year. But the next morning I woke up and took a test and it was negative.. A few days passed and I ended up started my “period” which wasn’t a normal period. It was the full 5 days but only one day was a “heavy” flow which was still lighter than normal. The rest of the days were super light.

Since the bleeding ended I’ve still had pregnancy symptoms but BFN HPTs.

I’m not sure what to think.. my fiancé swears I’m pregnant& says I could be 9 months pregnant and not test positive because I drink over 2 gallons of water a day 😂

I have a doctors appt scheduled but can’t get in for two weeks.

Any advice is welcome!! Thank you ladies!