Hi there! I'm a vegetarian too (mostly vegan, actually). Happily I seem to have no problems with soy but sometimes beans do bother me quite a bit. Melissa gave you some great ideas, but here are a few more :
- cereals and grains [whole or fortified] contain a good amount of protein
- leafy green vegetables are surprisingly high in protein (and iron!). I eat spinach cooked and pureed with no problems for my IBS at all.
- seaweed is even higher in protein - like kelp and spirulina.
- how are you with nuts and seeds? I'm ok with them if I have them in small amounts, and so I eat nuts and seeds often throughout the day, i.e. having about 1 tbsp of nuts at about 3 meals a day. Or a little bit of peanut or almond butter spread on some toast, etc.
- as Melissa mentioned, quorn is a really good option
- since you're not vegan - EGG WHITES! These are probably the highest protein food you'll be able to eat. Why not start each day with an egg white omlette? If you do that you can be SURE that you won't have to worry that you're not getting enough protein
- if you get sick of eating eggs, you can also get pure egg white protein powder too, which you could make into smoothies with water or rice milk or mix into homemade muffins or bars, etc. [If you're interested, this was discussed a while back on the IBS Fitness & Lifestyle Board - try doing a search of "egg white protein" there.]