oleander "soup" overdose

Is it possible to overdose on Oleander soup?
I was making my first batch "soup" and got excited about it right after the straining and filtering stage and drank about 1/3 cup. I actually thought I was going to die!
I kept telling myself that it's impossible to overdose, and have read others' posts about drinking it, so I tried to calm myself down.
My Oleander soup might have been stronger, too. I used about 3 lbs. (as much as could be stuffed into a 24 qt. pot).
I got "tunnel vision", strong deja-vu, hot and cold flashes, double-vision, and dizziness, with vomiting for about 2-1/2 to 3 hours.
Finally, with my stomach in a knot from "dry-heaving", I started to feel better...and better...and better...and better! I feel really good, now. Better than before. I had aches before that I think were from the metastasized prostate cancer in my bones and I think it's getting better already.
I'll try working up from a very small dose tomorrow, like I should have.

Back to my original question, "Is it possible to overdose on Oleander soup?"