Thank you all for your replies. Most people think I was lucky to have such a short labour - but I would have gladly swapped it for a longer one with a normal, term baby (which I was mentally prepared for!).
Everything seemed backwards in my labour, the contractions started suddenly, quite intense and were very close (only seconds apart), but as they got even stronger they spaced out, so I had 30-40 seconds or so in-between. It was quite a scary feeling - almost like drowning - as I felt I couldn't catch my breath or recover before the next one hit. What got me through was thinking that this must be transition as they are so close. It was a relief to push!
For my next one, if it went any quicker, I worry I would not make it to hospital. Especially if it hits suddenly like last time - as I was unable to move with contractions being only seconds apart. But it sounds as though it may not go quicker, especially if bubs stays in longer & my waters don't break early!