You probably have this term in your region but we always called eating/smoking too much weed as 'greening out'.
We always said "smoked yourself sober".
Concerning overdose usage: I do not equate overdose to mean death/near death experience. Most people I know don't either. Which is why you often here: "OD and died" or "overdosing" (meaning "not dead yet"). But yes I'm aware it can imply death. But it's more the risk of imminent death/getting close to death and not death itself.
I overdosed on alcohol once but I didn't die. I've overdosed on opioids many times and didn't die (probably should have). As a wee lad I even overdosed on cannabis once and puked my guts out because my body was trying to reject it any way it could (I did it smoking as well not edibles).
It's totally possible that OP's body just doesn't like CBD or he got something that really wasn't what it claimed it was and he slightly overdosed on it. A lot of drugs require an "overdose" to get desired effects (a buzz). For example, I doubt there is a doctor, chemist or researcher anywhere on the planet that would advocate for taking several grams of gabapentin in a 24 hour period. Yet people do it all of the time for a buzz. It's technically an overdose and the next day you can have bad effects like sore muscles. Which could be an indication that the person had a seizure while unaware in their stupor/sleep. Happened to me (I think) more than once.
One time I mistakenly overdosed on oxycodone+oxymorphone+alprazolam combo dosing over the course of 16 hours or so. Someone else provided the drugs and I was snorting large lines of what I assumed was oxycodone. What I didn't know was he was mixing oxymorphone in with each and every line. We snorted a week supply for two users with a very heavy tolerance over the course of that day without him or I being aware of it. Since he ate a handful of xanax bars and was crushing up pills probably ever 10-15 minutes without realizing it. We only figured it out when I took him home and he peeked in the bottle and saw he only had a few of each left.
Amazingly, I felt no ill effects other than nodding/being really buzzed until I attempted to leave his house for the drive home. We snorted one more pill before I left that I guess put me over the edge. My eyes started bouncing uncontrollably to the point where I couldn't see the road. I made it home and sat in a recliner. Started nodding and not breathing on and off for hours. Was convinced I was going to die. Was tracking time based on what was on my television. I'd come to about once or twice every hour, realize I was ODing again, try really hard to stay awake but always nod back off without any control. If not for my massive tolerance I surely would have died. It would have easily killed most anyone else. But somehow I made it. I felt like total shit the next day of course (well for several days).
By any measure the above was an overdose. A lucky overdose but an overdose none the less.
Substances also just act funny in different people. I can take all the codeine I want if I'm willing to deal with a horrible histamine reaction. You give my Grandmother a standard dose and she'll die. Any dose is an "overdose" for her. My friend can drink it like water and suffer no ill effects at all (and not many positive ones either). No amount is an overdose for him. Same substance different livers.
I see OP edited their original post and he's probably right. But it's important to keep in mind that even the most begin substances for 99.999% of the population can kill people that are unlucky enough to be in the 0.0001%.