I totally know how you feel. I'm terrble for letting my prescription run out and then not having the energy to get it done when I need it. THe longest I went without was for 5 days and I have never felt so low in my life. I'm also bulimic so I understand about being sick on the tablets!
It was tough, but you got through it. Try not to feel guilty. All I can suggest is to try your hardest to relax when you are in that situation....the more you worry and panic about not having your meds the more you feel like you need them Saying that, I also totally unerstand that that is easier said than done!
Hang in there, don't beat yourself up about it xxx