Sit down and create a list of all the things you will need to run a business and what they cost. An excel spreadsheet works very well for this purpose. To actually run a business you will need:
Business License for your locality (check at City Hall)
Possibly a state resale/sales tax permit.
A federal ID # - easy to get, you can do it online at irs.gov - not actually required (you can report under your SS#) but helpful for keeping your business finances separate from your personal finances.
A Bank account for the business. Most banks want your fed. ID #, not SS#.
Business insurance: liability (a must, especially for weddings), auto (business use is not always covered under a personal policy - check your state laws), workers comp, and general umbrella policy for fire/theft/casualty losses.
Letterhead, business cards, promo material, web site (yourname.com), maintenance of the site.
Reliable car and the cost of maintaining it, as well as gas.
Telephone, internet & utility expenses
Replacement fund for equipment, computer, software as they wear out, become obsolete.
Good portfolio. Don't underestimate how much this costs.
Bookkeeping program like QuickBooks, a good CPA to do the taxes (yes, the money is taxable as income) and a lawyer to write/verify your contracts.
Total this up, it is your fixed costs. Multiply by 12 and you have a years worth of expenses.
Then list all the costs for a job: gas, water, printing costs, as well as expendables: gels, batteries, cards, stuff that can be reused, but you always want extra and isn't expected to last more than one year. These are direct costs.
You then have to figure out a selling price that will cover both the direct costs and a portion of the fixed costs. This is the break even point. Add to that figure what you feel you should make for the labor and knowledge involved and add that to the break even value. This is your profit, what you pay yourself for working. You should research what other photographers of your skill level are charging. My guess is you are not charging anywhere near enough to cover the expenses outlined above, and they are barebones. http://www.entrepreneur.com/article/83808
This is not a business for the faint of heart or the less than 200?edicated. Sorry, photography is very hard to make a good living from and you have to work continually. You don't say if photo is your major, but I would hope you don't think this will be a profitable sideline business. It's not. Photography is an all or nothing kind of deal.