Before you know it you'll have a reason to stay. Before you realise what's happened you'll let someone talk you out of making a swift exit. Soon the fear will set in and every rational consideration will slowly morph in to something ugly- an excuse.
I've convinced myself to stay many times. Sometimes for my benefit, mostly at my detriment. I've stayed away from people, phone calls, emails, experiences, and ideas. I did it because it's easy to let fear determine your actions, and it's hard to recognise the differences between fear and rationality. Frequently the two are intermingled and in order to make a wise choice you have to spend time detangling the web. Sometimes the web is too tightly wound and you have to take a risk with only your conviction to propel you forward.
Your fears aren't alone, everyone else's will contribute to doubt too. Their fears, as well as your own may be founded in rational thought, but here is where you must realise the difference. Good decisions are based on an assessment of your goals, the possible outcomes, the risks and benefits, your ability to do what needs to be done, and the conviction of your soul. Notice how fears (yours or others') are not included in the list. So get out. Get away from your excuse to stay in your miserable mind set. Re-evaluate who you really want to be, how you want to live your life, and who you want to impact.
Leave your fear of change and unpredictability behind and never return to it. Don't mistake me, bring your reason, your discernment, and your wise counsel with you, but forget your fear. Your sympathetic nervous system knows when to utilise fight or flight, leave fear to the professional.
fear might keep you from making a sandwich on the top of a mountain
or eating banana chips on the side of one.