Feeling guilty going back to work

I’m currently pregnant and I have an 8 month old. I’m starting a new job next week. Monday through Friday 9am-6pm working at a preschool with infants . The waiting list is full so I can’t enroll my son .

I’m feeling guilty already and sad I feel like I’ll barely have time to spend with my kids . My 8 month old son goes to sleep at7pm . 😭😭 I’ll have weekends off. I’m living in temporary housing I can only stay for a year so I have to make money to get my own place. I’m a single mother so I have to depend on myself for housing. My sons dad will watch him and our new baby when he’s born . Any advice on how to balance work and life? Any tips from working moms?