I too have had a panic attack at work which left me unable to function, what was even worse is I had to keep trying to work (took a 30 minute or so break, then forced myself back up.. struggled that whole day/night lol) because of guilt I had of being unworthy, I felt the need to prove myself as the hardest worker and not let anybody down.
My tips would be:
-keep a bottle of benadryl around (if I'm not allowed to say benadryl I apologize) just encase you have panic attack like symptoms
-keep eating healthy, self esteem can go a long way and feeling good always helps
-pace yourself, giving yourself impossible tasks in a certain time frame can cause a great deal of stress, try to take it easy if you aren't trying that already
My heart goes out to you and I hope you can get over this unpleasant but ever so persistent hump.