Overweight and pregnant :(

Okay, so I have PCOS and have been struggling with weight loss my whole life. I gained 45 pounds with my last pregnancy and that was totally my fault. I ate like crazy, ate whatever I wanted and didn't work out so its no surprise that I wasn't able to lose the weight very easily...especially with my PCOS making it more difficult. 
I found out that I'm pregnant last week! Yay! It's a blessing especially since I was told it would be difficult to conceive again. 
But now at 30 pounds heavier than what I'm comfortable with...I'm really concerned about my health and this pregnancy. 
Since finding out I've cut out all fast food, cut out pop, no sweets and I've started walking 45 min a night (not much but it's something). Any other tips to maintain my weight while pregnant ? Any success stories from women who've been pregnant and overweight?