The life of a professional artist is full of ups and downs. In the same day you can receive the highest praise you've ever gotten and then get incisively critiqued (especially by someone who doesn't first show that they care). It's enough to make anyone have an occasional wish for an office job with clearer expectations and dependable strategies for advancement.
How do you deal with these emotional vicissitudes? One crucial element is having a strong support system (among other things this post doesn't have room for). I can't tell you how many times I've shared both my triumphs and frustrations (but especially my frustrations) with friends and family, and how they helped me put things in perspective.
It's also been essential for me to develop friendships with other business owners. By participating in get-togethers for entrepreneurs, I've become close with other people who are being disruptive (in a good way) by trying something new. They've been invaluable not just for commiseration, but in showing me how they dealt with similar frustrations.
If you're an artist, don't try to brave it all alone. Find people who care about you to help you through the hard times and celebrate with you during the good. And to everyone who has done that for me, thank you.