My dear Belle....Gold fish usually dies very quickly....try not to relate them to anything....
Stay focus and go forward....put the past behind and just be hopeful for a bright future....
Find a way to distract yourself from all these thoughts....anytime they come to you, do something to distract you....whatever you like....
take care of yourself and go out and sit under the sun....it will make you feel better.....even I found out if I have enough vitamins specially B12 and B complexes are helping me with my mood....Camomile Tea is good too....
Do you have fun friends that you can hang out with and forget all about Mark?