being healthy through Pregnancy

K
So I'm 5w2d and I'm stressing about weight gain I gained 4 stone when pregnant with my son and I've lost 5 since having him. 
I am still not small but much smaller than I was. 
I am desperate to maintain my weight throughout really (i.e. Be good but lose me and gain baby) what tips do you very gorgeous mums do? I just felt like a beached whale last time and am so scared will happen again!!!