There are a few options.

The principle of planning your finances is simple. But be firm about this principle.

Make sure that your family has food and living money set aside. DO NOT TOUCH THAT MONEY. Keep 50% more than your initial estimate.

Approach the bank you usually use. Ask them for a business line of credit. Believe me they are more than helpful to a doctor. (There are 2 businesses that are known to always make a profit - one is a doctor and the other is a dry-cleaner. If you do your job right, you will not have to do the latter.

Estimate your total fixed expenses. Double it. Ask for six months worth of working capital.

Another way of starting is to ask family/relatives. There is one big drawback to this. You will violate the time tested principle of "No business with friends and family".

If you have money in the stock market, use it for your own practice as this is most probably going to be the most profitable venture you ever undertook.