Hep B and polio vaccine question

Hi all! My LO is 8wks and 5d old and received a Hep B and polio vaccines yesterday. Last night she slept 8 and 1/2 hours straight and has been sleeping a lot today. My question is, is this normal? I cant seem to keep her up to eat long. It’s 330pm here and she’s only eaten 3 times. Twice for 20 minutes and once for 10. LO doesn’t typically sleep this much. It’s usually a struggle to get her to nap and at night she always wakes up around 4 to feed. Anyone else experience this? If so how long does it last?