Young mom with 3 under 3, send advice my way please

Hey mamas, im turning 21 in 2021 i just found out im pregnant with a third! Were so excited but i just had my daughter back in august so when this baby comes my oldest will be 2 years 7 months and my daughter will only be a year and a month. My son does amazing with my daughter so i know ill be good there❤ but I am worried about the toll it will take on my body and how to even prepare for a third because im going to have my hands full!(: but i was curious if any other mamas out there are/have been in my position and what helped you get through it, just any advice really! Thank you again😊