jaffacake, you're not going to be everyones cup of tea, none of us are - look at it like that rather than 'rejection'
It's a numbers game after all. Some people you mail, you most definitely WILL be their cuppa... iyswim.
It could also be that daters tend to have a sort of 'shopping' list, so look at your profile and count the ticks in the boxes... and my not open a message or reply based on not ticking one or two of the boxes even though you matched up to the ten other ones... if that makes sense?
It never used to bother me not getting replies or having mail unopened for the above reason...