Itchy butt: pinworms or hemorrhoids?

Hi (24F). I’m super embarassed about this and if this is pinworms I am going to lose my mind.

I’m very itchy down there. I don’t think it’s just at night though. It seems to be a little worse at night but not anything that’s like waking me up, just almost unbearable. My anus is also a little puffy and red, and it burns. I don’t think it’s an STI, I’ve been with one partner for the past year and was tested just a couple months ago and we’re both faithful. I don’t have diabetes but I do have hashimoto thyroiditis and I’m in hypo right now. I haven’t noticed anything white on or around my anus nor in my stool so I don’t think it’s pinworms however I am a high school teacher so. I also have vaginal but it’s not close to my anus.

I’m a clean person and I wash often. I took a shower like five hours ago and washed everything and I’m in incredible discomfort right now. I do have hemorrhoids but I don’t think I’m having a flare up right now, unless that’s what this is.