How much does your formula fed baby drink?

Kayla

We were exclusively breastfeeding but I stopped producing and have been having to supplement with formula. After a while my supply completely dropped and now we are only feeding formula. She will only drink 2.5-3 oz every 2-3 hours sometimes she’ll go 4 and she sleeps 1 6 hour stretch at night and then eats every 3 again. She is 6 weeks old. Is she eating enough?