I can't stop snacking on rubbish

I am eating chocolate, crisps and biscuits all the time, I'v gaining so much weight on my bum and legs and I feel like it's slowing me right down. i bought maternity trousers that had plenty of room in them a few weeks ago and now they are tight. I would say I was a bit in the skinny side before I fell pregnant but now I'm on another level. I love my baby bump and I am happy for that to go as much as needed but wish I had some control over the other parts, my legs and bum are huge. I'm going to need to start eating a bit more healthier. Anyone else the same just now?