I am also "obese" (revolting word) and was over 19 stone when I became pregnant with my dd. I had no difficulty becoming pregnant, although some overweight people do.
Despite some negative comments from one particular midwife, my weight was never an issue, and I wasn't weighed once whilst I was pregnant. I was monitored fairly closely, but this was because of my age (I was 38) not my weight. I did develop gestational diabetes, which was probably due to my weight, but it also meant I had to be a bit more careful about what I ate, which was probably no bad thing!
I didn't put on any weight at all right up until the last two weeks of my pregnancy, partly due to incessant morning sickness and probably partly because controlling my blood sugar meant I was controlling my eating a little more, too. No-one was too concerned about my not gaining weight as, being overweight, I had plenty in reserve, so to speak!
My dd was 8lb 7oz, disgustingly healthy, despite the paediatrician's warning that she could be born with diabetes or end up obese later on. She has no health problems, and at nearly 3 and a half she is a normal weight. Although it's getting more difficult to keep up with her now, so some of this weight has got to go!
My very best wishes, and I hope you can find the confidence to try for another pregnancy, whatever your size.