Anger at my partner

My partner and I have been together for 8 months but have known each other for 2 years. The past few weeks though I haven’t been myself with her. Once I get home from work we are happy and then an hour later I have this switch flip out of nowhere where I am angry and annoyed easily towards her. It is set off by the littlest things. I don’t know why because she hasn’t done anything to me to have me behave this way.
I know she sometimes doesn’t give me enough affection like I would want or she’s on her phone too much to where I feel ignored at times but those aren’t anything that’s new in our relationship.

She sat me down a few days ago and told me she’s scared to do anything because she’s afraid I will lash out. She’s afraid to not text me back, be late coming home or going out to do something. I didn’t even realize I had gotten this bad and my heart is broken hearing her say something about me that I was ignorant about. She asked what’s going on with me and I couldn’t even find a valid reason which has me feeling lost. Even the animals in the house have me on edge which isn’t normal. I’ve also been having a lot of depression and anxiety issues lately as well. Maybe it’s because of my new job or my family holding me to higher standards because of this new job. Ive only been with them for 2 months now and it’s the highest level I’ve been at with a ton of responsibilities. But I don’t know. I’ve struggled with anger before but never this bad. But I want it to stop because I don’t want to be this person.

Have you considered therapy for yourself?

The encouraging thing about what you wrote is your response to your partner telling you how she feels. To me, that is a great sign. If you said you didn't really care or just blamed her for everything, I'd be more worried.

It sounds like you have a whole lot going on right now and quite a bit of pressure, possibly from a couple different sources (one of them being you). I agree with @sarahsweets--it seems like some sort of therapy situation might be helpful. Having been in a couple fairly long-term relationships, I can tell you, if you don't address this, your partner is going to be an unhappy woman. And you don't want that.

I am glad she felt able to tell you how your behavior makes her feel, this is an opportunity to begin to explore your feelings and make efforts to change. Be honest with her. I hope you told her all that you said here. (I too have a "switch"-like mood change/shut down so I empathize with you---and few people have spoken openly to me about this, I am grateful for those who have). Do talk with her about your anxieties and anger (this may help prevent acting out). I don't know what you do to reduce stress and anxiety but I know, for me, physical activity has helped even when I have to force myself to move---eg, walking (maybe with yr girlfriend and talking), running, even turning up the music and dancing like a fool around the house is good for letting off some of that tension...) Check out some articles/information on PC re: anger/anxiety etc.