Hi there.
Just for tonight just stop everything and do something you enjoy. Watch TV, go for a walk, catch up with a friend? f you are in this mithered state of mind, it matters not what you do because you won't remember anything. You won't even be in a frame of mind where you can cope with anything. So get yourself in a mind set where you tell yourself it is OK, just breathe nice and slowly, get nice and warm and have a warm drink (or any other drink of fluids) Then get plenty of sleep. You cannot function without sleep, and expect to work and revise without it as well you will fry your brain cells (not literally)
What is happening to your head? Is it panicking or is it just firing off all sorts of questions and worries and then not shutting down when you need it to? It's ok to know that you are not coping very well. An overactive head is horrid. Is there a close family member you can talk things through with?
When your subjects get too hard and you feel defeated, focus on those subjects you enjoy and remind yourself everything will be as it is. You also have a lifetime of learning. You don't have to do anything but it helps. If 60% or more of your student colleagues give up - how much better does that improve your odds of getting a better grade? Your friends will get zero you might get an A. So just do your best, nothing more. Just try and learn two more key facts
a little bit more. Many of the most successful people in this country have very few qualifications, others don't even have a clue. So many people are not weighed down by worry and are not looking back at getting A's or B's or C's etc
Now use other people to help you over the first and the last hurdle. Your tutors can't do the work for you but they can assure you how you are doing with the end goal of exams in sight. Hold onto the positive, and drop any negative thoughts as soon as you find them. Use the 'MIND' site to help with anxiety.
Do go and get some emotional health support from your student welfare section, the health support bods or your GP. If you need to take a few days out, by all means do it but remember you can lose windows of time offered to everyone else and finally miss out on exams etc Just keep going even if it is on tick over.