Several things occur to me from reading through the posts.
One is that I do not see your goals of wanting to be with your girlfriend, work hours which coincide with hers, have more vacation time, and have fun at your work as unrealistic at all. To the contrary, they're definitely realistic, but you may need to do a number of things to reach them all and it may take a while. In other words, I don't agree that you have to choose between those goals for a second.
As far as locations, though, I do agree that if you insist on living in a small town (I have no idea if you do or not), you will probably have better chances of doing most things in a larger city and might need to move to one for a while if that's the only way to move forward.
There are many keys to doing well in Germany, one of the most important being to speak write and speak fluent, correct German, another to get as much professional training as possible if possible.
As you've seen, it's not always easy to get the required certificates but these are not required by all employers. It depends on the field you want to work in. Good office skills will also be useful in nearly any job nowadays. An excellent way to learn any current computer program is through www.lynda.com for $25/month - and there are sample lessons to try out first.
'Ex-Buchhändlerin' recommended temp work and I agree with her 100% for several reasons.
One, it's money in your pocket you get paid at the end of the week (or, actually, usually on the Monday after the work week), two, more importantly, several things happen: you get to know about different businesses, you learn skills, you get to know people who, if they're happy with your work, and you get along with other workers, will hire you permanently.
I no longer do temp work but it worked that way several times in different US cities. I can't speak for Germany but I'm certain it would work out much the same way. Businesses hire people (for the most part), not certificates. What you can learn at different jobs is worth a lot - it's paid on-the-job-training.
Still another route to consider, perhaps not right away, is to set up your own business doing whatever you feel you do best.
Why? You set your own hours, you're motivated because the more business you do, the more money goes into your bank account, you have tax advantages (you can write off many expenses), and you're your own person, not at someone else's beck-and-call. You have to please clients but that's very different from pleasing a boss. I did this in Germany, successfully, for 15 years. There's some bureaucracy involved and, of course, you need some startup capital, but it's possible and a great way to go.
In contrast to the suggestions of a few others, I don't think you need therapy at all.
You do need to sit down with yourself and your girlfriend to think through alternatives, you do need to write down your strengths and objectives, and reading 'What Color is My Parachute?' might, in fact, be a good idea, but spending time with a therapist is not going to get you a job.
He/she might help you to think through your goals but my guess is that you and your girlfriend could do a better job at that yourselves. I'd also say you've taken exactly the right first step by asking here. Look how many positive suggestions you've gotten already!
Don't worry about your age for a second. It's a cliche, but today really is the first day of the rest of your life and today is when you can do whatever you need to do to set up your future as you want it to be.