New to this - dairy intolerance

[pantsjustpants]

Ds is nearly and had horrid diarrhea for around 3 weeks now. I took him to the gp last week who would like to send of a sample to test for bugs, but we haven't managed it yet due to timing issues!

Around the same time we saw the go, I remembered that ds had a temporary dairy intolerance around this time last year. It cleared up easily and within two or three weeks we were reintroducing dairy with no problems.

This time it's not so easy.... I've bought some alpro yogurt and some oat milk stuff, although I think he's managed to have milk at play school yesterday. Please can I have some tips! I'm feeling a bit lost with it all.