If you want to talk to a helpline maybe try SaneLine. I just googled and they’re open until 11pm – I've emailed them before and they've been helpful (ish) so might be worth a try. Failing that there is always the Samaritans or Nightline if you’re at uni.
Some things I try when I'm feeling anxious:
Listen to a podcast or audiobook/ have an easy film/tv programme on in the background
Draw pictures/ play word games (such as finding as many small words in a big one)/ Sudoku/crosswords/math problems – stuff that engages you, but isn’t really difficult.
Play online games – I think it is a tradition in this thread to recommend infectonator
, but again anything that engages your attention
Exercise – maybe too late to go out for a walk but star jumps, lunges etc...
Breathing exercises/imagery tasks/mindfulness
Normally doing several things in combination helps me more than doing just one would, although often it doesn't feel like anything will help. Doing proactive things makes me feel like I’m taking a bit of control, which helps a little, even if the actual activities aren't very helpful, they're a distraction at least. I think the key thing to remember is that it will pass even if you do nothing at all, so while it’s horrible it isn't going to last forever and finding ways to manage and tolerate the feelings until they pass might help.