As cliche as it sounds, here is my answer.
1. Think Positive As You Think So You Are
I know it is tough not to have a job but raring to go and build a career. Look at it this way, you have a degree and a vocational qualification. How many people can claim that? All the things that you learned in these courses mean something to some employers out there. Think hard, surf the net to see who will need these skills. When you get ideas you won't feel lost.
2. Career Building Is A Journey
There is no need to rush. Yes, easier said than done but sometimes what seem to you as fumbling around is actually opportunities presenting itself. Get into a temp job that interests you. As you start, you will get to know people and soon one thing will lead to another. You will discover new strengths and interests and the opportuntity will present itself. Don't be afraid of being slow, only worry when you stop. Keep walking.
3. Start Somewhere
Grab a job that closest reflect what interests you and your knowledge. You mentioned you like working in an office, what industry might it be? List it down and give yourself some criteria that helps you short list the choices. It can be as simple as distance, size of company, type of industry and so on and so forth.
To round this up, I have currently two staff working with me with qualifications totally unrelated to advertising. One has a B.Sc in Biotech, and another a B.Sc in Entomology. They, like you fumbled through too. One now has 10 years experience and the other is only 2 years in advertising. Both are stars in my department.
Don't worry too much. It's all good. Just make sure you have the stamina to take this journey.
Keep walking and good luck!