Waking up to negative thoughts is never a way one wants to start their day. There are two choices. Let the negative thoughts consume the body and mind, and have it ruin the rest of your day, or reframe, accept, and release the thoughts, and have a more joyful day.
Being mindful can help you become aware of these type of thoughts, and find ways to release them, so the negative thoughts will not get out of control. You can tell yourself that you will not let these thoughts get the best of you. The day will be a good day. Accept what is, and if you can not accept it, than a change must happen. In the end, you control your happiness.
You can also try a meditation practice where you take a breath in(inhale), think about the negative thought. Immerse yourself in the thoughts, along with the feelings, and reactions it creates. Then release(exhale) the negative thoughts out of the body. This can be a helpful practice in releasing negative energy from the mind and body.
In the end, try not to let negative thoughts win. It is about having the best day possible, no matter the circumstances. Your happiness, and peace of mind depends on it.