iCloud Mail Not Always Sending

I've been using iCloud email for a couple weeks now and I love it except for one HUGE problem. I send emails or at least I think I do, but sometimes they don't send. In fact, they aren't in the sent items, aren't in the drafts... just gone as if they never existed. I did this last night three times in a row. I was sending an email to my work and I went to double check that it sent. 3 times I sent it but 3 times it vanished. iCloud email would be a no brainer for me if it was reliable. And I really wanted it to work. Very disappointed... would have made life so much easier.

Anyone know of a fix for this?