Sounds like my wife / soon to be ex. These people either spent a long time living a lie or they have a sudden change in outcome of life, I don't know.

You aren't sick. You spent 28 years with this person and it's normal to feel this way. It will get better, you need time becoming your own self again.

Concentrate on you. Make friends, start new activities, take care of yourself. You once spent a lot of energy taking care of him, now turn that on to you. Hugs!