Easy. Stop trying to imagine doing it the rest of your life! I’ve been doing it 40 years and I can’t imagine doing it the rest of my life either! God doesn’t give grace in advance of when you need it. Hebrews 4:16 says He gives “grace to help in time of need.” You don’t need it yet!
But He will give you grace to get on the phone tonight to make a few calls!
Also, you may not be called to being supported by donor gift income for life. Called “for now” is okay. One day at a time.