Is this an alter or a mood swing?

Hey -

Been having a hard time telling the difference between a very strong, very intense 'mood' and an actual alter trying to speak to me or get out? Doesn't happen all the time. I can usually tell what's going on, but I'm confused about this:

Since I got home (site of most of my trauma), my mood swings and switching has been so rapid and intense I can barely stand it. Whatever, right? I deal. But one 'mood' concerns me in specific, and it's IRRITATION. For example, the washing machine finished its cycle and beeped and I felt this sudden, very foreign feeling of rage/frustration/irritation, so strong I got nauseous and my body felt like it was burning? It's happened several times for no good reason at all and I'm really, really not allowed to express anger in my house so I have to hide and then I start crying...and then I have to go to sleep or lay down for a bit because it's extremely exhausting...

I'm wondering if this sounds like a bad mood swing/pent up anger or if it sounds like it could be an angry/annoyed alter? For the most part I can't really hear or speak to my alters and it's all very emotion and image based. I'm wondering if this irritation feels so foreign because it's actually someone else?

If it turns out to be someone else, does anyone have any recommendations on how to effectively approach this alter? I'm going to try to journal it and hopefully something comes of it.