I had this very ambitious idea to do 10 really cool games in 10 days but I'm suffering from depression right now and I feel like the best I can do is 5 if I split them apart 2 days. The results won't be eligible for this jam anymore - since they won't be made within a 24-hour period, but I would like to know if I can still mention the jam via a Twitter hashtag and on the eventual project page?

Hey, take care of yourself and participate in whatever way is best for you. You're definitely allowed to submit any/all of these projects to the jam, there's no shame in taking a bit of extra time to make a game! The limitations of VMJ are in place only to give you a good game-making experience, so as long as you're doing what you can, I encourage you to submit (your games, that is) and consider yourself a fully legitimate jammer.

* edit: Or another way to word this is, 10 games in 10 days is meant to push you "to your limit," so if your limit is 5 games in 10 days, I want you to feel encouraged to try your hardest to achieve something that feels achievable. The ability to be honest about what you think you can accomplish is an invaluable trait, imo.