Screaming baby who won't sleep

This will be short because I'm so tired... My baby stays up for hours at a time and only will sleep for 45mins to an hour tops. She will fight sleep for going on 5 hours and just screams. I'm miserable and it's making me have bad thoughts. People are saying it must be my breast milk and that I should switch to formula. I fought SO hard to be able to breastfeed..through my baby's tongue tie, mastitis, and thrush . It just got easier and now this is happening. Should I give up? Crying as I type this. My baby will be 7 weeks on Mon