Try to make something challenging, but try to be reasonable to keep yourself from feeling overwhelmed.

If you feel a lot of resistance towards working on a game or jam then you should just start small, anything is a win and you can build on it in the future.

Planning things out properly helps a lot to get a better mental image for your game and scope, it helps you to see the steps and process more clearly.

Working with others is always an option and might allow you to focus more on a particular skill.

If it doesn't work out it's ok.

But you sound motivated to me, at the end of the day if you don't try, you won't know.

Get a plan, don't wander aimlessly with a mechanic you like. Have an idea of what you want the game to be. Don't stress out over having to leave things out, its fine. Watch your back for scope creep. Take breaks, its 2 weeks, you got time! 

how i do that is by trying to make a huge list of ideas i want to do, then narrowing it down bit by bit, and even if you can't narrow it down to one just combine multiple of them for a really wacky idea. make sure the idea is:

A: Fun/Creative(if its another generic platformer then its not fun)

B: A fun theme(does not have to follow game jam theme)

C: Not too challenging to do(only 2 weeks boi)

if you are unmotivated or sad

try to start doing something

share with us a picture of your work

we will find the pros (or cons) of your work

it may help you