I was 91kg and size 16/18 when I fell pregnant. I was pretty healthy at the time, despite my weight (ran a 10km fun run two days before my positive test) and kept up training as much as possible until about half way through.
But, looking back, and I was probably a bit PFB and took it too easy on myself. I also have sinus polyps that one day need to be surgically removed, which affected my breathing. I felt pretty breathless from about 20 weeks onwards if I exerted myself.
I gained around 25kg, partly because I was not eating as well as I should, partly because I had SOOOO much fluid and swelling which affected my mobility a lot (I suspected this was also due to me being fat, but that's completely my opinion). By the end I could be up and about for about half an hour before needing a 10 minute rest.
Other than that I had a healthy pregnancy. Got tested for diabetes twice, but clear. I ended up with an EMCS due to labour not progressing and DS being in distress, but I had a very good recovery. Lost 15kg within the first month but the last 10kg didn't shift. I would bet that was the extra weight I gained by not remaining active and eating well, and I would have put that on without the baby, IYKWIM.
So my advice to you is to try to limit your weight gain by eating healthily and remaining as active as you can and you will likely have as good a pregnancy as anyone else.