Exercising questions

So I am a 30 year old male who has always remained in decent shape. From the time I started 7th grade I had a 6 pack by 9th grade I was running a mile in 4-4:30. Running was my favorite thing to do and I was always running. My problem started when I developed severe stomach problems and was diagnosed with ibs 6 years ago. Ever since I have been unable to do any real heavy exercise and the last time I tried running which would have been a year or year and a half ago it felt like I tore my stomach apart afterwords. I've been scared to try ever since. Problem now is I'm starting to notice I'm getting out of shape and overweight and it is really affecting my mental state now. I looked online and read running or any other high intensity workout can be really bad on stomach issues. So my question is this does anyone know anything I can do besides just dieting that can help me lose weight get back in shape and possibly even build some muscle? I'm not asking for sugarcoated answers here either if your answer to me is suck it up and accept the fact that if I want to fix it it's probably gonna hurt a bit then I'm more than happy to accept that. I'm just looking for any advice I can get.