L.H.
Hi A.,
I don't have the name of a psychologist near you. However, I do have experience with a now 16 year old. Don't rule out drugs. Yes, even in 8th grade. That is when my son said he started. Lots of kids do start then. Some handle school work, play sports, maintane a reasonable family relationship. Then there are the others who just can't handle how good it makes them feel without getting addicted or at least don't see the downward spiral they are in.
Getting in to see a psychologist is a great idea. I suggest you look for someone who will counsel you in how to stay close to your son while still setting boundaries and rules. Everyone I know says teenagers are terribly difficult. Hopefully, you are just dealing with typical behavior. But when you say his grades have dropped and he doesn't care those could be signs of drug use.
Best of luck.
L.