idk if i help but i can ollie sumthing like half a metre but idk if thats high?
anyways apprently u land like a manual, well like dan i had that prpoblem, what ur doing "wrong" is
you dont either,
1. u dont pop high enouff to slide or
2. bascially you dont slide
when i ollied i forgot to slide, and it ends up like that,
but another thing is u might popand when you slide you slide 2 early (i kno thats sound stupid but maybe)
and the board gos down to quickand your nose/tail smashed the ground and like that.
ON YOU TUBE the best vid that helped me ( looking at 500+ vid this was easily best for me ) was a
The Broken Bear people who told me, i dont kno exactly what there called but u should try anyway, i would do a link but im new idk how to sorry bout that...
how to do it... first bend your legs( thats key to succsessfully ollie ) then put prescure on the back tail while u jump so as u jump it natully pops correctly because the pressure leaves then ull be in the air higher or lower depeneding on how much presssure then you'll have loads of time to slide... HOPE IT HELPS
EDIT: check out my detailed how to ollie ^^^^^^ is short and kinda a on the top of my head post lol