This question has many potential answers, so let's spend some time narrowing down, eh?
I've got some questions, and from there we can probably give you better answers (aha, probably? No, definitely.). Alright, I'm just gonna number the list, I hope you don't mind my lack of narrative consistency.
1. How long exactly have you been using that batch, and how do you store it? It's possible that you have some form of contaminate (many possibilities here) or you are adversely reacting to compounds that the original alkaloids have decomposed into. Also, what strain is it? What is the smell like? Pictures might be helpful.
2. How long have you been using kratom before judgement day-or-so (I'm gonna use that to refer to your 1g H and 70mg diazepam.. submergence, shall we say?)? Daily?
3. Since you had quit cannabis (or rather, a few days after-- so we're sure you weren't experiencing cannbis' residual effects) had you taken kratom before the judgement day-or-so?? It's possible that kratom is aggravating certain aspects of your cannabis withdrawal. Or perhaps cannabis was minimizing this side effect for you and you hadn't noticed until now. Those two ideas are almost the same thing though.. Still, please answer whatever questions I've asked. I just wanna help ya, as I'm sure we all do :3
Oh, and please describe your cannabis use for the past long while, if you would.
4. It could also be exacerbating a benzo withdrawal, but I need to know more about your usage history to get anywhere with that. So, over the last 6 months or so, what has your benzo use been like?
5. Did you notice any unusual effects from the heroin? A cutting substance could have been irresponsibly chosen, thus administering large doses of antihistamines, research chems, or even synthesis impurities. This could have damaged any number of systems, I guess. I'd need to ask all you people about what you think about my ideas/lines of questioning. This is an interesting situation, to say the least.
6. Have you been trying to use everyday (or at your previous usage level; without answers I'm just masturbating my mind here) since the judgement day-or-so?
7. I want to ask you about your seroquel use, but at dosages like yours (and I assume you've been on it for a long time) I don't foresee this having to do with the seroquel. Though perhaps seroquel's effect's on the dopaminergic systems and cholignergic systems could be the true root cause of all this. So how long've you been using seroquel to sleep?
That's all I got for now. I hope we can help you figure this out, mon ami. Being kept from a substance you enjoy because of nasty, sudden onset side-effects is one of the worst feelings, so I really want to help you out. It's also one hell of an interesting puzzle of sorts.
oh, and finally 8.) Have you made any changes to your diet, supplementation routine, lifestyle, or anything like that?