You did a nice job for something done in a week!

If you want the true kind of scary, the feeling of unease that shakes the player to their core, go for a more psychological approach than just a creepy light and a cheap jumpscare. Use the environment to terrify the player (this can be more than just spooky sounds and a dark atmosphere), create illusions, and make the game play the player. Constantly make the player expect something scary to happen, so that they are too busy shaking in their seats to focus. 

This can be done through interactable objects/characters, a fleshed out environment, and definitely a fleshed out monster. What is this monster? Why is this monster after you? Where did it come from? Can you kill it? Does it have a weakness? What does it like? What does it dislike? How does it hunt its prey? What can you do to subdue it long enough to survive? You as the dev should have the answers to these questions, so that you can set up clues in the environment, objects, and the monster itself to reward the player for figuring it all out as they play. 

Take the car you have to repair for example. Why is it here? Why is it in pieces? Why are the pieces where they are on the map (Where did you get a map??)? Can the monster even to stop you if you escape in the car? And if you repaired the car, where would you go?

Plus, the player's ignorance of these answers can make the game scarier! We fear what we don't understand, after all.

Consider some kind of façade at the beginning, as well. Lots of scary games have an unusual setting at the beginning so that the player is subverted when the scary part hits (Doki Doki Literature Club, Omori). Maybe you're out on a lovely vacation in the wilds at first, or you're just trying to enjoy a relaxing picnic.

Keep it up!