I'm so glad someone replied!
Your case is quite similar to a few of my friends: you know what you want to do, you've even done a little bit of work towards getting into the area, but it's hard to get a sense of the "lay of land" so to speak, let alone breaking through and securing some sort of paid work.
Before working in admin I wanted to work in a gallery, but they can be cliquey places if they are small or if they are big you don't get exposed to all the different areas. After over 6 months of internships I gave up because I was no closer to getting paid or understanding where I could fit in. Now gallery work just obviously wasn't for me, but I have seen loads of friends working years for free in order to get their foot in the door. I think there is another way to going about it though, especially if you are super passionate about the area: take on a little personal project.
Ok don't judge me, but I love the podcast Millennial (
http://www.millennialpodcast.org). The first 10 eps are basically the creator explaining how day-to-day she's going about establishing a career in online broadcasting after graduating. It's a really great insight into another persons thought processes but for the purposes of this discussion what's really interesting is how the creator builds podcasting experience, not by working for free, but by just doing her own podcast. I think there's a bit of scope doing something like this (even at a smaller scale) in your position. For example, have you noticed a gap in mental health support somewhere? Maybe there's something you can do to fill it. It doesn't have to be big, it could be as simple as setting up a Twitter, Instagram or blog and building a following. Maybe even getting in touch with a charitable institution and seeing if there's anything you can do together. Sometimes I think self motivated work looks better on the cv than endless internships, plus it doesn't matter if you don't get paid because it's your project and you can dictate its limits.
Hope this helps, maybe I'll open up in a little bit and talk about what I'm interested in.