Hello eyes louder then words..
Welcome to the forums..
I can relate to you having nightmares of a night, and waking up in panic mode...I think myself personally that if we go to sleep without calming our mind these nightmares become more frequent..
I started meditating at night once I got into bed, then I would listen to a peaceful sleep story on you tube, most times I fall asleep before the person telling the story has finished...and I find the nightmares are not happening that much anymore....maybe you could try doing something like that once you get into bed...
Can I ask you if you have professional help with your anxiety...or have you spoken to your gp about your nightmares..your GP..might set you up on a mental health care plan if he/she thinks it will benefit you..
Also deep breathing can help to calm your racing heart when you wake in panic...Slowly in counting to 4 slowly..then hold for 5 then out for the count of 7 slowly releasing your air...then repeat a few times...
Please look after yourself the best you can..and talk here anytime you feel up to it or in need of some support..
My kindest thoughts with care..