Sincerity plays a huge role in your life right now, so if you're not willing to do something, don't agree to do it. Avoid the statement: 'i'd be happy to... ' uttering these words will create all kinds of boundary failure and resentment. So, if you don't want to start a new project, remind him or her what's on your plate. The key is keeping yourself sane and maintaining your sterling work ethic.