Just eat fruits, green vegetables, fish, rice and drink water or tea for the next few days and see if the symptoms go away. Fresh meat and root vegetables should also be ok.

Avoid grains with high protein and fibre. No floury things, oats and pysllium husks for the time being.

My friend who is possibly gluten intolerant or celiac noticed the breathlessness stopped almost immediately with the diet but the constipation took longer to go away. Lots of money spent on doctors but they could not find out what's wrong. So we did quite a bit of searching and reading online and we realised that the symptoms were possibly related to GI because we had been on a high-fibre diet of oats and cereals. I was ok but my friend has not fully recovered yet and is still looking for a doctor/hospital to go for tests.