My advisor shared my unpublished/ongoing work with another student without notice
There are two things that you need to address here: your advisor sharing your work with the other student, and the other student's request.

Regarding your advisor sharing your work, you should talk to your advisor about this but do NOT express anger. S/he was probably doing what they thought was best and did not realize it would upset you, and it is VERY important to keep a good relationship with your advisor, so I wouldn't start a fight over this. Just a simple "I appreciate this opportunity to help them with my methods, but I would appreciate it if in the future you would check with me first before showing my drafts to someone." or something similar. Keep it low-key, do not go in angry or expecting an apology, just express your preference for how situations like this should be handled in the future.

Regarding the second situation with the other student -- ask them if they'd like you as a collaborator on their paper! It's never too early to start working collaboratively!