First off, congratulations on the birth of your little girl!
Screaming with distress at 6 weeks when breastfed can indicate a few things.
What you eat affects your milk, and that can distress the baby. Caffeine, loads of pulses (for example if you're veggie/vegan), too muchg fruit (we got a juicer and it upset my seond baby's stomach because I was drinking more fresh juice than his system could tolerate) or allergens like dairy, egg, nuts, etc can all pass into your milk and cause your baby distress.
Reducing your intake of possible irritants and seeing how she responds can be one option. Another is for you to switch to drinking fennel or camomile tea which settles the stomach and see if she is more comfortable with that.
It's also when colic appears. There's lots of advice available online for that. My eldest had colic and I can only send all my sympathy - it was absolutely horrendous.
Look up ways to wind your baby - each baby has his/her own preferred method. That reduces a lot of distress.
It does pass, and it does get far easier. You're doing brilliantly. Take any help available, and rest at any point you can.
Again, huge amounts of sympathy to you, OP.