You are not off the hook right now.
Depression is shitty, but treatable. I speak from experience :)
Something like that can also just come suddenly – as Kensington already described. With such life events, people simply reconsider things in a totally different way.
When I was 18, I had terrible panic attacks and anxieties. What you describe, the circling and clinging to the bad things, you don’t just get out of that easily. Things that helped me back then were distracting myself (if possible) and getting help. There are therapeutic counseling centers, I had good experiences with those.
Therapy may be exaggerated, but maybe not. Maybe this is a "trigger" moment that shows you that you are not doing well.
But that also means you can seek help now. General practitioner, or google your place of residence + psychological counseling center, you will definitely find something. I just looked for Stuttgart, there are quite a few.
As JuliaMünchen rightly pointed out – this pandemic is extremely stressful, plus a life event and maybe other worries that previously had no space...
The most important thing for you – there are help centers, find help. See if you have friends or your wife who can support you with that. Open up if possible and seek help.
I sincerely wish you all the best.
And wait it out for now, you are in an exceptional situation. Let the notary be the notary and take care of yourself first.