Don't panic.
For now, I'd say eat mainly what you feel like, but keep a balanced diet and eat things easy to digest rather than, e.g. alcohol or huge fatty meals. You may also do better avoiding fibre. But don't try and make radical changes at once, you'll learn over time what is best for you. If you're very underweight or if you feel food is having a big negative impact, maybe ask to see a dietician.
Are you on medication? Do you have an IBD nurse? If your doctor - whether it's your GP or your gastroenterologist - is really not helping you, you can ask to see someone else.
Have a search online and you'll find plenty of useful info. If anything you find scares or confuses you, if you like post about it on this forum and someone will help you figure it out. Remember that you will not have the same experiences as everyone you read about. It takes time to get your head around having a chronic illness like this - your life will go back to feeling normal again.