I hope im not alone

I have a 18 month old boy and a 3day old baby girl my older one is acting up he tried to hit her but was nice at first I show him alot of attention so he doesn't feel alone but it hasn't been enough I guess I just wanted to know im not the only one having a hard time with the tantrums and being jealous I love both of my baby's vary much I just feel like I'm the only mom that's going through this