First time IVF (fresh transfer)❌

Just got the dreaded call from my doctor that the beta was negative. I had a feeling it didn’t work but am still confused as to what happened. We did everything by the textbook. My husband and I are both relatively young- 31. We have unexplained infertility. We transferred a day 5 blastocyst that the embryologist said looked great. It was already beginning to hatch. I ate the McDonald’s French fries right after the transfer, did bed rest, ate pineapple core, Brazil nuts, and pomegranate my god just about everything I could think of. I keep thinking we should’ve done the PGS testing even though my doctor said it wasn’t necessary for us. We still have some on ice so are planning on doing a frozen transfer next cycle and perhaps putting 2 in rather than 1. Has anyone gone through a failed fresh cycle and have a successful frozen cycle?