All of us now and then experience nights, when we do not sleep so well. That is perfectly normal and true even for generally good sleepers. Not always, but sometimes, we can identify the reason for a bad night, for example we may have a stressful time at school or work. 
Interestingly, stress can also be positive, for example something you are really looking forward to and excited about. In such situations, sleep can suffer, because stress makes it challenging to relax and calm our minds. 

However, sometimes, experiencing trouble sleeping may itself become a source of stress: You lie in bed, waiting for sleep to come, you worry about the future, about not being able to perform or just manage everyday life, and you may even feel as if you will never be able to sleep well again. This restlessness of your mind can then also translate into bodily sensations of stress: Perhaps you feel your heart beating against the wall of your chest or your muscles tighten. And when you then get up the next morning, the daily hassles may just overwhelm you. 

Fortunately, most sleep complaints during a stressful phase are short-lived and will sort themselves out once the stress is gone or by using relaxation techniques. However, there is the risk of them becoming independent from triggering situations and becoming chronic. In this case, you should approach your GP or a sleep expert.