There's a joke I like where one wanting independence goes from an employee working 5days a week, to a business owner working 7 days a week! Anxiety, frustration and doubt is normal and there are sleepless nights in the beginning. It's not a cakewalk otherwise everyone will be doing it. You will have setbacks, and progress is made from both small successes and small failures, you will face both. The biggest lessons come from the failures. It doesn't feel good.
As time passes you learn what works and what doesn't. You learn your trade and you learn people. The workload and stress becomes more manageable at the same time, your earned experience hones your process and increases efficiency. You business may shrink before it grows, you work hard, you learn to compartmentalize. You work hard! I could go on, but I'm sure you get the idea. Check your emotions, and lastly, work hard.