Weird experience while taperingish

I've been reading through a lot of posts here as I'm trying to taper down my dose (back sliding occasionally while I figure everything out) to get off of this stuff and starting late last week to earlier this week when I got a certain strain in from a reputable vendor I've been having symptoms others have while quitting when I take a dose. I've been through pwd before and this definitely isn't it. When I took the other strain, both at my regular dose and at lower doses, I'd get tightness in the chest and arms, weird sorts of headaches and all of that during the time after dosing where I'd normally be feeling what people take the stuff for. I lowered my dose significantly while waiting for a different strain and form to come in from the same vendor and have the same affects but to a lesser degree. The other stuff came in and i, foolishly, took it at my normal dose and got the anxiety in the chest and some tightness in the arms and occasionally legs and I would have circling dizzy spells. Mind you the new stuff I got in is highly regarded and no one else on the telegram had anything like I was experiencing from either strain. I lowered my dose of the new stuff as the affects weren't as bad as with the other stuff and today I took only 40mg 12.5 hours after my last dose last night (my rec dose it 65-70) and, again, I had the seemingly wd like affects, just to a lower degree. On the one hand it's a blessing in disguise cause I'm ready to taper and get off of this stuff, already ordered MIT for when my dose gets low enough (going to hold out as long as I can today and when the wds kick in I'm going to take another 40mg.), there's no point in taking this stuff if it makes me miserable everytime I do. I'm wondering if anyone has had anything like this or has any insight? (on a side note, if it matters, I've been constipated for a good while now because of this stuff so idk if that matters or not, but I don't have bms near as much as I used too.) I'm also wondering what doses of MIT I should take and at what point to start adding it in.

I'm absolutely perplexed as I've ordered from this vendor many times before and even the same strains and this never happened and now I can't seem to escape it. I'm dreading my next dose and somewhat worried that something bad could happen, though that just may be the anxiety talking. Thanks in advance.