Bf is on some kind of stimulant

So he tends to have racing thoughts, sweats, huge eyes, slurred speech, he’s fine one minute and angry the next. He also will drive faster and not realize he is. I have came home and the house has smelt like chemicals like I could throw up. He randomly here recently just started having a major addiction into something. He called off our wedding and says he doesn’t even love me anymore randomly. He will try to talk to me about it and he’s sweet towards the night but during the day he’s angry and hateful towards me about it. He will also say something and then contradict that thought with something else. Like he told me “I want to work on things” two minutes later “I just feel like we are growing apart”. It’s extremely confusing and hard to deal with. During the day he walks super fast everywhere and just has to be doing something and doesn’t eat hardly at all. He lies to me about it but it’s not hard to tell. He’s constantly itching and picking at skin. I have no idea the steps of dealing with this? Like it’s so emotionally draining to deal with and we have kids? I know the person he can be and that’s what’s hard but I have to accept he may never want change and I’m extremely sad about that.