I did something similar my first time, but i had 6 Stim Canisters. For me, that was very challenging. You can't purchase any stim canisters, they're only findable in game, and you can have up to 10 total. Unless you're on Story Mode, this isn't going to be easy for you. Here's some advice on how to succeed with Trilla.
Save your force powers to counter her unblockable attacks (or that shockwave thing she does), or have a clear shot for a really strong attack.
Your most powerful attack is your split-saber attack in dual-blade mode, when you have a clear shot, hit her with that to knock her health down fast.
When she lunges at you, always roll to the right to evade her without getting hit.
When she puts her lightsaber away, either push or pull her, or find a way to dodge, or she'll force-drain you and the ttack is pretty devastating.
Use your precision evade to generate more force whenever you can. Keep just a little in your force bar to get you out of trouble.
