Landlord Concerns Unsafe Living Conditions

I am a F35, living in MA. I have lived in the same 3 family home for about 3 and a half years. The place is in very bad shape. Last year the building was purchased by a new owner, a first time landlord. She is very kind, single mom; but I am having a lot of issues. For 6 months we had defective fire detectors that JUST got changed a couple weeks ago. The building has a bad mouse infestation. She had told me she wishes everyone was clean like me, but despite my efforts to clean, I found 6 dead mice in just one week…. I went months with a broken drop ceiling in the bathroom because a squirrel fell through, I’ve told her about the broken drop ceiling in my living room that squirrels run across and I’m scared another one is going to fall through. I went four months with a toilet that leaks so bad every single time you flushed it that literal urine and fecal matter were always on the floor, and I had to mop every single time I flushed. I’ve had to throw away hundreds of dollars of personal items and food because it was covered in mouse droppings. It’s so bad the first floor tenants just up and left. Then, squatters were there! For at least a week, maybe two. They found drugs and everything…. They got in because the back door to the building is broken and can just be pushed open, or it could have been through one of the broken windows as well... and now it’s been 2 months since I told her that the heat doesn’t work, and she still hasn’t had it fixed, I had to start staying elsewhere because it’s too cold and I can’t afford the cost to keep running space heats, my electric bill was 875 because she’s not fixing this! I told her that I plan to move out at lease end which is in May, but I don’t even think that’s right I want to leave now and quite frankly I think I should be reimbursed for the two months that I also didn’t have heat. It’s in a really bad neighborhood which I know is out of her control, but, she also isn’t taking security measures to ensure the building isn’t accessible to the drug addicts, she keeps saying she will change locks and put up cameras but she hasn’t. She has admitted she got scammed when purchasing this house and she didn’t realize the amount of repairs needed, and how expensive it is and how she’s barely making enough money just to cover the mortgage and other bills associated with the house. I feel bad but I think I need to report her because this hasn’t been fair to me either. What step should I take to get this resolved?