You're venturing in a new direction in your life. You're making some pretty big changes.
Here's my number one tip for avoiding self-sabotage:
Start paying attention to the people you seek support from when starting a new path.
For example, you want to quit your crappy job and go back to school to become a physical therapist. It's a long program and hard work.
Watch your habit of going to the same people you know won't support you, and will confuse, cast doubt, or judge you. ("Are you sure you want to do this? You don't usually stick with things you start," etc.)
Because here's the thing: it's not really about them. It's about you.
It's natural to want their support. I do too. It's human.
But one day when you notice you're not happy and haven't been for a while and you're working hard on real change, it's really important to start building new community. Seek out people who are themselves excited about growing and evolving, and will support, challenge, and inspire you.
You don't have to sever ties with your old family or friends! Just recognize that you know what you're going to get from people who've been in your life for a long time. So focus your time with them on the things in which you are aligned instead of the things they're not going to like.
And start seeking out people to support your new growth. They're out there. Start to see them. Practice noticing them.
Be deliberate about who you share your new journey with.