Thanks for you replies everyone, they mean a lot! I actually am up and about and emptying my bag on my own today, so slowly getting used to it. I know it's only a little thing, but it's making it all a bit more normal. Are blockages quite common? I have been eating quite a low fibre diet since yesterday (when I was allowed to eat again!), I am hoping I can go back to more normal foods as I have been eating very low fibre/ minimal the past few weeks when things have been flaring up. The pain is so much better for sure, I have to remember that! All I have now is healing pain (from the surgery) which is about a million times better than what I was experiencing last week!
I was told it's best to wait 6 - 8 weeks to introduce blockage-causing foods as the stoma is still swollen until that time, meaning the opening is smaller and things can more easily get stuck.
As I said in my post above, just a small amount of blockage-causing food made me very ill. The reactions were so dramatic and so well-correlated with my attempts to change my diet that it was clear what was going on.
I think my reaction is more extreme than most; read most ileostomy sites or information leaflets, and they usually tell you that you can expect to resume a normal diet, full of fruits, veges, etc. and will maybe only have to exclude a couple of the worst offenders or choose better options (e.g. cooking veg well, avoiding pips and fruit skins but eating fruit). I certainly got the impression from my stoma nurse that it wasn't a dire emergency if I ate one of the foods that we're warned about - yet for me that is what it amounted to when it came to it.
So I would say that while many do go back to being able to eat fibre, there are exceptions - like me - so introduce foods carefully. Before I had a blockage, the changes in my diet led to my stoma output become full of hard little bits, whereas normally it is smooth, and moderate stomach cramps. After a couple of days of eating like this and with this bitty output - blockage. Another try a couple of weeks later, a much smaller amount of fibre, and I was back to stomach cramping and nausea.
So I've given up on the idea of a normal diet for myself. But it's not too bad, my diet isn't really that limited in most respects. It's just the lack of fresh fruit and veg that gets me down a bit. I can do alright with some very well cooked veg in very tiny portions, tinned pears and fruit juice, bananas and stewed apples. Plus some other things like smooth tomato soup. I do without whole grains, dried fruit, nuts and seeds. In terms of vitamins I think I get what I need, though my diet does feel unhealthy since I lack fresh greens and whole-grains, even though, for me, it would be far more unhealthy to risk eating them. It's hard to think beyond all the messages we're bombarded with about healthy eating, which doesn't account for those of us with unusual digestive systems!
Edit: an important thing I forgot to ask: what kind of stoma do you have? This may make a big difference.