I would like to say how sorry I am you have lost your husband. I've read some of your posts going back over the last 4 years or so (helping others as well as your own threads) and realy feel for you to have this on top of everything else. Sadly love has penalties.
I can understand maybe some of what you are going though. My wife of 25 years passed away after a long illness, the last 9 months of which just about totally consumed our lives. Like you the grief was overwhelming and I became suicidal again. In addition my life had been tailored around giving support, now that all stopped.
I say again because I had PTSD, anxiety and bouts of depression which began long before this. As to how you sort out what is depression and what is grief I've no idea. I too had been regularly visiting a long-term psychiatrist for meds and therapy and this sort of morphed into grief counseling sessions too.
I can't advise you on ECT. if you Google:
ECT beyondblue forum
you will find many threads on the subject, some old and some new.
I"m not really sure how I got though. The psychiatrist and my regular treatment helped. Going to work and trying to lose myself in it did too. The hope that one day I'd meet another soulmate provided a glimmer. As for what else rest I'm not wise enough to say except hte patience and love of family and friends did help.
I did find someone else and 20+ years later we are still in love.
If I remember correctly at one time you found art and craft to be an avenue you could use. Can you steer yourself in that direction now? Anything to distract the mind and step outside the constant grinding grief, even if only for a moment.
Also may I ask if you have anyone to talk to? I endlessly repeated myself, hard on others but I think it helped.
You are welcome here