Sorry to hear that, hopefully you will be ok soon.

Last time I was cancelling a P fare TPAC ticket, I had the option to get a refund to CC less cancellation fees, or get a refund as the form of credit voucher equal to the ticket price. I would suggest calling in (or even try it online) and see if you have the second option.

Also, if you discussion your situation with a supervisor, there is a chance that the change fee will be waived.