I have PCS from getting 2 mild concussions 10 days apart from each other (the first one was in 27 October 2014).

I have a couple of questions regarding what I should do:

1. I'm taking Ritalin on a daily basis to treat my ADHD (this was not caused by the concussion as I've always had ADHD). Can this slow recovery and harm the chance of making a good recovery? I think it might slow my recovery (because Ritalin is a potent psychoactive drug which is a powerful stimulant), but I'm not sure. Can I keep taking it right now?

2. I'll have a field trip of my school in about 2 months from now. The trip's length is 2 days, and involves many physical activity and physical challenges (some climbing, walking on rocky mountains long distances and such). Is it safe for me to go to that trip? I'm afraid that the physical activity, such as walking and jumping on rocks and stones might be very bad for me because of my concussion.

So what do you guys think?

Thanks,
-ProAgonist