Because that nagging little inner voice can run riot and stop you in a heartbeat, despite your best intentions. It might say things to you like:

You don’t have the guts to step up and find a new life;
You failed last time why will this be different now;
You won’t be able to face life alone;
You are not worthy, who will listen to you

Any or all of these may manifest as procrastination, overwhelm or a dull heavy feeling, a feeling of dread or a gut-wrenching quiver of how will I face the day. Or a vague feeling that is more out there to live.