Wait.. you haven't heard from your friend in 11 days, or your friend began doing meth 11 days ago?
That's a long time to go without hearing from someone. Your best bet is to not ask for advice on a website where people may not get back to you immediately, but instead call proper authorities (911) ASAP. I hate to say it, but your friend may have overdosed if they are a first-timer.
Get help now.