So I gave it one more try...
After a fairly long break from any opiates, I decided to give poppy seed tea another shot. In all my previous attempts, I'd only really gotten mild effects at best. So I decided to use twice the dose I'd done in the past. Usually I'd have started with a small dose to gauge strength, but this brand had been fairly consistent for me in the past, and assuming they were of similar strength, I didn't want to waste any on a smaller dose as I wouldn't have had enough left for a stronger one. They were standard, supermarket purchased seeds and given my previous experiences, I was expecting little, if any effects. As it turns out, I'd vastly underestimated the strength of them. Around an hour after dosing I was feeling very pleasant, but over the proceeding hour it continued to increase in strength to a stage I wasn't quite comfortable with.
I felt incredibly sedated, and a strong urge to fall asleep. It took all my effort not to - I wasn't sure if that was a good idea on a high dose or not, since I felt like I needed to concentrate on my breathing (otherwise I'd forget to). My pupils were also incredibly tiny, something which I don't think I've experienced from poppy seed tea before. The effects were felt strongly for at least 8 hours, during all of which I felt like I would pass out at any second. I'd planned on watching a couple movies while on the tea, but I ended up being too out of it to do anything except lay on the couch completely zoned out.
In many of the past threads about tea someone will always mention to be careful dosing due to the variance in strength, and to start out low. That's great advice, and in retrospect something I should have considered yesterday when I consumed my dose, instead of assuming they would just be weak like in the past.