It's a well established medicine! It's just been phased out for the newer antihistamines that last 24 hours. But sometimes, that older medicine just works better, for us at least.

I do hope you're feeling better today! Sorry, I was not trying to push any "alternative medicine", just suggest something for bad days to add on to your routine. It is a well established medicine, but it does look like it may be prescription only in Europe (or at least in the UK), so not helpful...