I remember I felt that way after I broke up with my ex of 2 and a half years. After you spend 2 years sleeping with a person in the same bed, the sudden change is like a shock to the system. You can't sleep, you just lie there staring at the ceiling.
I ended up moving out of the place completely, that made the transition a lot smoother for me.
Don't cry, don't regret and don't blame
Weak find the whip, willing find freedom
Towards the sun, carry your name
In warm hands you are given
Ask the wind for the way
Uncertainty's gone, your path will unravel
Accept all as it is and do not blame
God or the Devil
~Born to Live - Mavrik~