Baby fever

Hello so i am 27. Been maried for almost 9 years to my amazing husband we have 3 kids a son who is 7 almost 8 a daughter who is 3 and a 10 month old daughter. I have extreme baby fever already to the point my heart will feel heavy when i think about being pregnant again and adding another one to our family. Being a mom is my favoritething in this world. Ive never had postpartum depression all 3 pregnancies went pretty smooth. Deliveries were kinda Scary but i honestlyam craving having another baby so bad and it wont stop i think about it all the time. Anyone in a similar situation how has it been having 4 kids? I feel guilty wanting another baby while having a baby whos is only 10 months like i should let her be the baby longer. But the feeling in my heart just wont stop and it is such a strong feeling. How hard is it to have 2 under 2 as well as two older ones?