How to get over a character's death
Short answer: You don't. But the least I can do is help you cope with it.
*cleans glasses fancily*
The first thing that comes to mind is tears. Lots and lots of TEARS. And yes, that IS one of the components of it, but there is so much more in the mix here. Below, you may find the result of overly procrastinating...
Studies have shown that a fictional character's death impacts three of the five thousand, three hundred and seventy-two humanoid feelings that most likely assault you whilst reading.
Consuming oxygen and the lack of it that occurs the moment you KNOW the author's going to break you into a thousand pieces.
Emotional breakage that shatters every piece of willingness to continue suffering.
The sinus pain from intense sniffling.
Since we already got that out of the way, let's continue with the things you can do to minimize the side effects of all that.
First, make sure TO NOT RE-READ THE LAST PAGE IN WHICH THE CHARACTER WAS ALIVE BECAUSE THAT WILL BE DETRIMENTAL TO YOUR HEALTH.
Secondly, please don't start searching for fanfiction or fanart of said character at LEAST until a 48-hour period has passed and your eyes cannot take any more of the suffering and must succumb to even MORE suffering because duh, that's what a sane human being does.
Thirdly, keep the steady flow of reads as this will cause the pain to lessen as your memory commences to yeet the dead character to the back of the pack.
To the fourth element, learn to despise the author, therefore giving your frustrations (WHY IN THE HECKING PECKING WORLD DID THAT CHARACTER HAVE TO GET KILLED) a healthy outlet.
Fifth and last coping advice, strive to move on from that certain death. They shall live forever in your memory and your arms will always be open TO A FRICKING SEQUEL IN WHICH THEY DON'T PERISH AND WHERE MY DREAMS ARE NOT STOMPED ON REPEATEDLY BECAUSE SOMEHOW, SOMEONE SOMEWHERE THOUGHT THAT IT WOULD BE A MARVELOUS IDEA TO KILL THAT PERSON.
So yes, I as Dr. Booksy, shall prescribe a few medicine supplements to avoid extra Emotional Breakage and to make sure all of you are getting your Vitamin B.
Bonus Tip: Eat your weight in pastries.