It is compulsory to pray Fajr prayers and every prayer within it’s
time before it lapses (i.e. becomes Qadha). The Mo’min must do
everything that he can to perform all his prayers within its time.
You need to change your sleeping timing to be sure that you can wake up
to perform the Fajr prayer. The Hadith says : He who sleeps during the
time of Fajr prayer and misses the prayer will be called from the sky
: O loser !
If for any reason like illness etc. You could not wake up for Fajr,
then you must perform it as Qadha on the same day or better as soon as
you wake but that can never be usual procedure. You need to set an
alarm or request your family members to wake you up or your friends to
phone you to be sure that you wake up for Fajr prayers on time.
According to authentic Hadeeths, the loss of a person missing Fajr
prayer is more than all the treasures of this world.