Little things can trigger me to lose the plot, i threaten to kill myself, i'm verbally abusive, smash things then i go back to normal. is this bipolar?

It might be, but: Whatever the eventual dx, it is a good sign that you can step outside for a moment to see how distressed you can be and that something goes very wrong at such times. Find a good psychologist to help define a DX and a successful treatment plan. It may be bipolar, but other possibilities exist too. It is worth a full exam to get this resolved as well as possible - your future will be the pay-off!