Agree with seeing the doctor to rule out other things. I think that is an important step as there are a number of other things which can give IBS type symptoms including coeliac and early stage stomach ulcer.
As a lifelong sufferer of IBS (I can remember having it when I was three) I think it is partly triggered by stress, so is better when I take time to meditate or exercise, and partly due to gut sensitivity.
I can eat sugar and wheat but too much of either triggers it ( and I am an old gimmer so I spotted this at least 40 years ago before it became fashionable to demonise those things) so I wouldn't eat bread and pasta in the same day. I don't seem to be triggered by dairy or citrus which apparently some people are.
Probiotics do seem to help a bit if I remember to take them. If you have developed IBS as an adult after something like gastroenteritis then I'd say they were essential for at least a few months. You can buy some high dose ones from health food shops aimed at e.g. people travelling to third world countries and anecdotally these work well.
I have spent periods of my life for a few months at a time eating only protein and veg. If I do that I have no problems at all. However life is too short to eat like that all the time.
I'd suggest you keep a food diary noting how your gut feels before each meal and 30 then 60 minutes after it. I always know within half an hour if I've overdone it. I suspect you will see some patterns fairly quickly.
Personally I think Fodmap is a pretty depressing diet, but you could try moving to light protein and veg only for a week or so (no grains) and see if that helps then gradually introduce other things. The "good" thing about IBS is that if diet is a component you see it quite quickly.
The other thing I'd say is to get yourself some imodium or better still the cheaper generic alternative. I find it works well and quickly and carrying it in my bag gives me the confidence to know I can manage it if I need to which reduces the stress element. Also oil of peppermint capsules are effective to soothe gut cramping.