It is acceptable that a PhD student becomes ill during his studies, as long as you have a doctor to confirm your condition. You should approach your research director and explain the situation. Any student that has been unwell for some time can have an intermission; it is up to your Faculty’s discretion though the extent of it. This is what really matters even if your supervisors are not happy with this course of action. It is very convenient for supervisors to demote a student if he or she is not progressing according to their expectations. My advice would be: do not give up yet! It is a genuine and out of your control situation. Thus, you may be surprised how much people in management care. Perhaps you will be able to have a back dated intermission. Good luck!