IBS and weight lifting exercise

I've been diagnosed with IBS and was referred to a dietitian that offered me treatment with FODMAP diet which has greatly improved my symptoms. I am still though facing  an annoying with weight lifting exercises. I find it extremely tiresome that whenever I go to the gym and try lift weights, I literally feel my body gets "shut-down" and I feel extremely tired and unable to continue with the exercise. Do note that I don't try to over-exercise or lift too much weight, not at all! It is truly annoying, has anybody ever experienced that? what can I do to improve it?

IBS can leave your bodydrained and exhausted. Be careful. Listen to what your body is telling you. If you feel more tired or unwell maybe give it a miss and just go for a walk.

I get this every so often. Happened twice this week actually. Once when u was shopping g and I suddenly feel completely exhausted and another time was the gym. 20 minutes into my work out it was like I was a tub and someone pulled the plug. I just immediately drain. I have asked a few doctors by it but they shrug it off. It's so frustrating.