Scared of getting "big" & gaining weight

At delivery of my son I was at my all time high weight. Took me 13 months to lose all the baby weight plus some and to be happy with my size and weight for the first time EVER. I lost about 70lbs from birth to 13 months post partum. I'm 14 weeks, I gained a couple pounds of bloat early on due to pregnancy and stopping my strict diet. Other than that I haven't gained but I'm scared of gaining, I will be crushed as that scale starts going up and my belly and body start getting bigger. I look at myself and think of how I need to eat better (because of morning sickness I've been eating a lot of junk and carbs) because I can already see my belly is bloated and beginning to grow and how I was to be "thin" during pregnancy or for as long as I can be before I really pop. Obviously I know I will gain and grow but I'm just having a hard time accepting it, even if it is for a good reason.