Well from your post, I would say that you are stressed out. Stress will aggravate your IBS, so I recommend relaxing as much as possible. Find some light exercise that you enjoy, for example, I like to go on walks in the morning when my belly is unhappy. I also find that abdominal exercises help in the morning if i am having some morning sickness. Also yoga helps me control my symptoms. I try to do yoga or light stretching in the morning everyday because it makes me feel good all day. Stress about the symptoms or something else in your life could be causing a physiological response, stress is incredibly powerful in that way. Really focus on reducing stress and being happy. I found this helped the most for me.
I notice that a lot of people who have IBS in general have weak pelvic floor, so i recommend practicing stomach vacuums on an empty stomach.
Look at your posture and try to make it ideal as possible, many people who sit a lot and are stressed often make the psoas incredibly tight. You mentioned some breathing problems, and i would recommend looking into ways to softening the psoas out, such as myofascial release with a slightly deflated ball. That will help with the breathing which in turn will help with the stress. I too struggle with breathing problems sometimes, so take some long deep breaths and if you feel tightness in the belly try to 'breathe into it'. I like to practice breathing exercises with my back and feet on the ground and place the hands over the belly and focus on breathing using only the diaphragm. You should feel the belly rise and fall with each breath. Slow and steady, Especially focus on making the exhale slow, full and complete.
I am genetically lactose intolerant and I struggle with digestion in general. I recommend keep on with the fodmap diet for at least three months. I also supplement with HCL+pepsin before meals heavy in protein or fat. Stress can lower your HCL production in your stomach and it might be in your interest to supplement with them for a while at each meal. I also like to drink hot water with lemon juice first thing in the morning, this helps me evacuate first thing.