Likewise, if you feel exhausted, despite getting a good night's sleep, then you may be expending way more energy analyzing what's going wrong, and it's making you fatigued. All that stress can make you feel anxious, and you may notice that you're eating more as a result of being stressed. Then again, that worry can cause a lack of appetite. Regardless of what you're eating, stress can cause gastric problems like nausea and constipation. A state of emotional unrest can affect your immune system, so watch out if you notice yourself getting sick a lot with colds or other infections. Similarly, if you find that an old injury isn't healing well, it could be a result of your flagging immunity. For your physical and emotional health, if you start to see several of these signs, then it's time to break it off.