You will need to discuss your phobia with your physician and ask him for a referral to a mental-health specialist. Since a phobia that causes such a severe reaction is a medical condition, I cannot help you with that beyond encouraging you to seek proper care for it.
What I can help you with is how to cope with receiving the sacraments while pursuing treatment. If you are able to go to Mass but feel yourself unable to receive Communion, you could forego receiving Communion and make a spiritual communion instead. Catholics are not required to receive Communion at every Mass they attend; they are only required to receive once a year during the Easter season. You could put off receiving Communion at Mass until you feel better. If it is only a fear of priests that disables you but you feel able to receive from someone else, you could receive from a deacon or extraordinary minister if they are available.
If your condition renders you unable to attend Mass (or if you need to meet the Easter requirement and are unable to do so at church), you can ask your parish to send an extraordinary minister of holy Communion to your home to bring you Communion. Most parishes have programs to bring the sacraments to the homebound and would be more than happy to accommodate your need.
That only leaves confession, which you must receive from a priest. You might try anonymous confession (i.e., confessing from behind a privacy screen) rather than face-to-face confession. If that doesn’t work, I recommend consulting with your health-care provider for techniques for coping with your phobia during the time it takes to confess.
