Hello and welcome!

It doesn't sound anything like Bipolar to me. Irritability is a potential symptom, but it isn't the main one, and it isn't required for a diagnosis. A lot of people with Bipolar don't even experience irritability. People with Borderline Personality Disorder tend to be more explosive, but that's also a very complex diagnosis with a lot of different symptoms.

I don't really know if the weed might mess with her mood or not. It has a negative effect on my mood, but I have psychotic symptoms during manic episodes and am probably not the best reference case.

Honestly, it sounds like this is probably in the domain of a therapist or psychologist rather than a psychiatrist. It doesn't necessarily sound like mental illness to me... more like anger issues. But that's for a professional to say.

I hope things work out for you.