first to relieve stress and negative thoughts is to stop thinking for a moment, relax, empty your mind and begin to refill with a focus on finding the most sensible way out of the existing state.
Do not judge yourself for our thoughts and feelings. Basically, nothing can be said to be "good" or "bad" for thoughts and feelings. Know that we can not control every thought that comes up or the feelings we experience. What we can control is the way we interpret and respond.