Blood shot eyes

I’m worried about my 16 year old son. I have noticed recently that he has often got blood shot eyes and that he is spending more time than usual alone in his bedroom. My immediate thought is he’s up to something, like smoking weed. Though, there are no other signs that this is true.

C – Son has blood shot eyes
T – He’s up to something
F – Suspicious
A- stare at him looking for clues, avoid his room for fear of what I’ll discover, ask him if anything is going on again and again, don’t feel satisfied with his response, catastrophize, think of the times he’s lied to me in the past, seek reassurance from my husband, don’t enjoy being around my son.
R – I’m up to something, creating a story to punish myself with

(Not sure this R is right?)

It’s almost as if I can’t be satisfied until I 100% know the truth, but I can’t really know the truth.

We have drug tested our son in the past but that created such a huge disconnect and distrust between us, we said we wouldn’t do it again.

I have dropped my manuals for him in many areas like vaping, though it was hard, but this feels more serious.

Please can you help me get some perspective here?