My question involves landlord-tenant law in the State of: texas

I was living in a 2 bedroom, 1 bath, apartment in bad conditions, when suddenly circumstances came up that put me in a position to have to move out because I would no longer be able to pay rent. I had not been there for about 2 weeks visiting family and when I came back I promptly moved my things out and accepted that I would break my lease and get a bad rep on my credit. I had no idea that we shared a joint lease, as most places around here no matter how many people living in an apt, all have separate leases. So this affected my roommate but there was nothing I could do. He has found a new tenant to replace me and I ended up owing about 300. He wants to take me to claims court for it. Is there anything I can do? The living conditions were terrible, the place smells of dog piss/shit all the time and he even moved in his girlfriend without my permission or even discussing it. They smoked weed all the time and pretty much ruined the condition of the apt. I only owe about 300 because I helped pay 200$ which I really thought I didn't have to. I have been threatened and harassed via text messages and phone calls by his older brother and him.