Figure out what is really causing the stress. Think of as many possible causes as you can, and write them down. Now brainstorm for solutions that will reduce the stress, and commit them to paper. A trusted friend, family member or school counselor may be able to offer some good ideas as well.
No. The most common reason for denying a grant is a donor's desire to use that grant for table sponsorship or event tickets. When you make your initial contribution to a donor-advised fund, your contribution is 100% tax deductible.
Your local school is likely nonprofit and a branch of the local government. If so, yes, the donation is tax-deductible. See also IRS Pub 17, which has some duplication from Pub 526: Organizations That Qualify To Receive Deductible Contributions.