SAHM Advice Needed

Hello ladies! My hubby and I are TTC. We both would love if I could be a STAM, but have no idea how to make it work. Currently we both work full time with overtime. We have somewhat of a budget, but don't stick to it religiously. I feel like if I quit my job when baby comes we will really struggle. Not only will it cut virtually all of our "fun" money, but it may make even bills and groceries pretty tight. I guess how do you make your budget work? Any tips? How do you quit your full time job without feeling guilty about money or stressing about it way to much? Tips? Advice? Support? Thanks!