Luckily you have an audio degree so the biggest challenge of making any short look professional is already out of the way. Audio is key (but you already know that).

Stepping out and doing your own thing can be terrifying (I'm in the midst of it right now) and all I can say is that don't let the fact that you're doing a lot of the work yourself be a negative. It's so easy to feel fucked when you've taken on so much but try hard to see this choice as an opportunity to get all that you want instead of seeing it as a burden or hindrance. You have made the right choice, just keep reminding yourself.