Try position the bed under the window and use shelving to mimic a headboard.

is it a dorm room?

No, it’s my room in my house

The room would look a lot better without the shelf, and a larger piece of art on that wall. If you really need some of those books in this room, I would get rid of everything on the top of the shelf, and take out as many books as you can part with too. Paint the shelf the same color as the walls. Move the unit to be centered between the corner and the closet if you have enough clearance between the bed and that closet wall. Better yet would be a shorter, wider shelving unit. Maybe with room on a shelf to hold that backpack.

Hi! I would recommend to remove the bookcase and add corner shelving. Add your books, decor you like, plants and lighting. You can even skip one shelf to place the existing painting you have there.

You're asking for redesigning of your bedroom, that's not only about a bookcase it's about the entire room. Perhaps your room might work better with the bed under the window but without more pictures (all 4 walls) and/or a floor plan showing all dimensions it's not really possible to give valuable suggestions.

Would love to help. Please measure your room indicating placement of doors and windows. I would be happy to do a scaled plan. Also, what size is your bed? What is the window sill height?

Here's an inspirational photo for your room that could probably be done affordably. Paint the bookshelf you have in white then get a white bookshelf the same size for the other side of the bed. Get some much nicer bedding and curtains.

Alternatively, move your current bookcase to the side of the bed now to see if this would work.

Add small night table on the other side. Do paint the bookcase white eventually. You have such a small space, don't break up the visual field with dark colors.

In the future:

Here is how to post a Design Dilemma to get the best results. You need to show the whole space—all four sides of an entire space—even if it’s about one specific Dilemma. A layout fix is often a Design Dilemma fix even if it doesn't seem like that. Commenters need to see doorways, windows, closets, finishes throughtout the space to make informed suggestions.

State right at the beginning what the room will be used for and who will use it. State the non-negotiables at the beginning, what has to be kept. Give some idea of the budget. And provide approximate measurements

https://www.houzz.com/discussions/6417709/unofficial-design-dilemma-boot-camp

Keep in mind that you're inviting some design pros and people with a design eye into your home via photos. If they walked into your actual space, they would take in all of it: all four sides, doorways, floors, windows, ceiling, built-in fixtures, lighting, trim--the "givens"--then the features that can be changed--furnishings, paint, art, rugs, decor items, etc. It's all one first impression. Same thing with photos. That's why it's important to provide well lit photos of the entire space, taken from all sides of a room regardless of the size of your problem.