Hugs from me too. That stinks no matter what caused it.
As far as invitations dwindling due to declines ... well, that happened to DH. He has (had?) this immense pack of very close friends ... most of them since elementary school, or at least high school. (DH is now in his early 40s.) We used to go out with them a lot. However, over the past eight years or so:
DH and I had son No. 1, who has a disability. Cue lots and lots of doctor and therapy appointments.
I went back to work full time when we had to start worrying about DH's job.
DH lost his job; eventually found a new one working all nights for much less money. That means I had to keep my full-time job working days, really curtailing our schedule.
We had DS No. 2.
Obviously, over these years, we really had to cut back on seeing people.

We really wanted to see them, but we didn't have much time, or money, and had to respond in the negative to invitations.
So perhaps I understand why the invitations dried up, but the fact was, it hurt.

We really didn't want to see people. And there were times when we might have been able to make something happen. But we didn't get the chance.
One of the DH's oldest friends was back in town one weekend ... something that rarely happens. DH would have loved to see him, and I would have moved heaven and earth to get him to any function where Friend would be. But we didn't get the chance. DH only found out about it a week after that fact in an offhand mention from another friend that he happened to run into at the grocery store.
He's still heartbroken about that.