Are you stressed about work or your relationships or anything else? If yes, you have probably been able to identify the cause of your sleeplessness. Stress can affect your sleep in different ways. You may end up sleeping for 12 hours or more or you may just not be able to sleep at all.
Sometimes, an event such as the death of a loved one or an accident can cause stress. This is, of course, natural. Keep in mind that it's not only negative situations that may lead to stress. Positive situations such as planning a wedding or even a vacation can be stressful for some people.
Basically, what you need to do here is to change the way you react to stressful situations, whether positive or negative. If you are constantly anxious about work or a relationship, you probably need to change your attitude towards the issue. Or just bring about some changes in your job or relationship status?