How long are you taking off?

I got approved for 12 weeks unpaid. I have no pto or sick time, only savings for maternity leave. I was planning on taking 8 weeks off but last month my son needed surgery and now we owe almost $6000 for that. So I’m thinking about only taking 4-6 weeks off.. my first I took off for 10 weeks but felt like I could have gone back sooner but idk about going back at four weeks.... I work two twelve hour shifts a week. I’ll be going into debt if I take the 8 weeks