Whether or not you can lend money to someone or borrow money from the company is a matter of the corporate documents. It also might involve your partners and whether they would approve of the transaction.
A bigger problem is that there is the appearance that you are commingling business and personal funds, which may result in a piercing of the corporate veil.
Now as for the accounting, you should check with your accountant. I don't believe you will be able to write the loan off.
This answer does not, nor is it intended to, create an attorney-client relationship or constitute attorney advertising. Rather, it is offered solely for information purposes. Since the facts of each case are different, it is critical to consult with qualified counsel with whom information can be shared and assessed under an attorney-client privilege, so that competent advice can be obtained on which you can make informed decisions.
The answer to your question depends on the formation documents of your company. Typically, in many LLC Operating Agreements, there will be a provision that allows Members to take out loans from the company. It would be wise for you to seek counsel on this matter from an attorney as well as an accountant.