Really high anxiety levels

Hi, I have a 14 year old son with ASD and since before Christmas his anxiety levels have been really high, but this week things have got a lot worse...he can’t go in any lessons at school and his whole personality has changed.

The one thing that scares me is his eyes, at times they shake from side to side though anxiety I think but he is snapping and just really isn’t his happy smiling self.

would anyone have any advice for me to help him?