My cat is upset all the time

It all started a few months ago when my dad brought a kitten home. My cat (10y.o) didn’t like her from the first moment, to this day she (my cat-M) is still not used to her (the kitten-T). M is always making angry noises when she sees T, hisses at her, attacks her. Even when T is not around, she still walks around making angry noises as if she’s angry at us? And no our behaviour didn’t change towards her at all.. She hisses at us too, and attacks us too. She was never the type of cat that shows a lot of attention but before all this we could at least pick her and hold her, she just won’t let us anymore. She won’t let us even touch her sometimes. Shes just always upset. And we don’t know what to do, obviously we were tried to buy antidepressants and stuff but she won’t take them. What is going on with my cat and how can we help her?