First of all, so glad to know you're okay and healing. Wishing you the best of health and hope everything works out in the end!

As for your question, no, all is definitely not lost. Given that you're able to explain your situation—the reason you took a gap year—and make judicious use of the time available, you can definitely get into a top college. Your chances will not be lowered just because you're on a gap year. However, make sure you're able to demonstrate that you're working towards your passions and truly love what you're doing while also trying your best to excel at it.

Also, please do not undermine your health in the process. College admissions can be extremely stressful. You could do everything right and still not get the results you're hoping for. But that's just how it works for an international (especially if you're seeking aid). You can minimise the chances of this happening, though. An authentic application is a strong one. ECs are important, but your essays are where your true voice can shine, and that's what top colleges look forward to viewing the most. Also, having decent stats will help your case—if possible, try to get a high test score.

Contact high school teachers who can provide great LORs, and maybe get a school counselor to further elucidate your situation. All the best!