I feel for you! I'm up because DS is unsettled after having D&V all weekend. He's now asleep and I'm wide awake, of course!
Heartburn was the bane of all my pregnancies - I had it so badly the other day that it felt like my chest was being crushed or I was having a heart attack.
To be honest I could never pinpoint anything causing it either - it didn't matter what I ate/didn't eat, when I ate, if I ate and I tried every cure! The only thing I've been doing is taking gaviscon and going to bed while it works so I can get some sleep.
Hope you feel better soon and congratulations on your pregnancy!
Runningforme - I agree about Saville. I met him once and was repelled by him. After he left my friends and I all agreed we'd never met anyone who made our skin crawl so... then someone commented that her friend nursed in Leeds, where it was well known that the nurses never left him alone and followed him round the hospital... so he wasn't trusted, and people had their suspicions.