..oh, I didn't realise it was THAT person..
...what you did by emailing was fine and what most people would do and if he does forget again then it's ok to email in again in a few days ago because that's probably what you would do anyway and you're only feeling awkward and self-conscious because of what your friend said..?...but I don't think there is any need to because he probably doesn't feel at all akward and you want to be able to communicate with him about uni stuff without overthinking it...honestly, he is probably just a scatter brain or has had a busy week, so try not to think or worry about it..