The most important thing that OP has to learn is that he is not alone, there are professionals out there that can help you. But you have to make the first step.
In Germany, if you have public insurance and your GP prescribe therapy to you, but all public therapists are fully booked, you can take sessions with a private therapist and the public insurance is obligated to cover you.
This is true, that's how I'm getting therapy right now. I was scared this was too much paperwork for me at first, but my therapist explained that I basically needed to only do three things:
(1) go to a GP (Hausarzt) and explain my situation so they fill up a report and confirm that the issue is indeed psychological and not physical,
(2) go to a therapist that works with public insurance so they can write another report, your therapist might refer you to one of his/her colleagues, and
(3) email five therapists that work with public insurance and ask them how long their waiting list is. They likely will all tell you it's longer than 3 months, which is what you need to hear.
You basically send this stuff to your insurance company and they deal with the rest.
1. Talk to your health insurance; they often have scheduling services
2. Talk to the Kassenärztlicher Bereitschaftsdienst of your state, e.g., Bavaria has this on offer: https://www.kvb.de/service/patienten/terminservicestelle/ter... If you don't know where to head to, call 116117. Easiest way.
3. Go to your GP - he can guide you through this or can forward you to a psychiatrist
4. Use the online service from the association of psychotherapists: https://www.psychotherapiesuche.de/pid/ersteschritte
If you have suicidal thoughts, search for a local Krisendienst Psychiatrie (https://duckduckgo.com/?t=ffab&q=krisendienst+psychiatrie&ia...), they can help you immediately.
The most important thing that OP has to learn is that he is not alone, there are professionals out there that can help you. But you have to make the first step.