Hi there
6 weeks sound about right for a growth spurt. Babes do grow at their own rates and at this age, it's normal for them to be waking several times at night for a feed. My DS was fine on the growth charts and I was told to wake him to feed in the night if he didn't wake by himself. If I had my time again, I'm not sure I'd follow that advice now though!!
Thing to remember is that right now, their whole job is growing. That's it. Your job is making the growth possible - feeding. They will know when they need to feed, generally. Babes all grow at different rates and their tummies aren't all the same size, just as Mamas don't all produce the same amount of milk (it even differs from a Mama's right breast to the left!), so that's why at this young age the most important thing is to follow their hunger cues and their demand rather than EASY timings for feeds. At 6 weeks, I'd say if they don't show hunger cues from 3h after the start of the last feed, try to feed. At night, I'd hope for a 4h or so stretch during the core night but it's a hope. As long as you get those feeds in regularly during the day (3h) you get a better shot at a 1 longer stretch between feeds at night.
As pps, might settle back into the old long nights pattern once a GS has passed or it may last a little longer. Growing at her own rate, digesting the milk at her own rate; it's your LO's call
Things you can do to help. Graze during feeds in addition to eating regular meals - so have a sandwich, some fruit, snacks, large glass of water at each nursing session. Stock up on milk building supplies to eat and snack on (I grazed through night feeds initially too) - I found bready cakes and muffins etc helped keep me fuelled. This will help your milk supply, which is her growth fuel, and might give her the calories she needs to go a little longer at night.
And congratulations on your happy little arrival! Enjoy the time you have together - they are never this age or size again. These feeds are a great time to get to know eachother and share the journey. Easy to say in hindsight, but I wished I'd taken more time to be in the moment. They are gone so so fast
HTH
Charlotte x