Parents with dairy allergy, did your LO end up having a dairy allergy too?

So I've recently realized that I've had a dairy allergy all of my life. Not full blown lactose intolerance, but I believe I have a casein/whey allergy. I completely eliminated dairy from my diet a few months ago (unrelated to this believe it or not) and yesterday I ate some butter by accident. Now my body is feeling gross. I won't get into the details but after researching, I have all these signs throughout childhood and up to now that point to a dairy allergy.

My 6 month old is EBF and since having that butter yesterday and feeling its effects I noticed my boy has a slightly stuffy nose now. Not sure if it's related but I know this could be a sign of a dairy allergy in a baby.

Anyone with any experience with this? I'd be interested in getting tested but I heard it's not super reliable, is that true?