Anxiety at Work Worsened by Coworkers

I have generalized anxiety disorder, with depression of course, so I tend to be on edge anyway. Lately work has been worsening this. I have barely anything to do other than check-out patients and answer the phone occasionally. I just sit there and ruminate all day. My mind wanders; sometimes I'm lucky and it's just daydreams, but sometimes it's all the bad things. Is my mom okay at work? What if she gets hurt? What if they call and I don't know and something happens to her? Then I just snowball into panic and get that sinking feeling of "I got to get out of here!" I'm not allowed to do anything else. I've asked to use earbuds and could at one point, but all of a sudden they're not allowed. My psych recommended planning the most extravagant vacation possible, down to little details, so I'd have something to do at work. Well, manager decided that was misusing the computer. (Despite others using it to shop or chat.) Lately, things have worsened to where two of my coworkers up front have a private chat. How do I know this? Well one will type a lot, then the other will laugh and type a lot. Then the original one will laugh and look at them. It's just repetitive. My third coworker gets in moods where it makes her mad and she vents to me which just adds stress to me. Yesterday, I glanced over at the third coworker, one I considered a close friend and 'work mom'. She was in a private chat with the other two. So the three of them have a chat that I'm secluded from. We're a group up front of four, so to me this is detrimental. I'm devastated. I was angry and called my mom to vent. But today I'm just down and anxious. I feel like I need to leave, but then I have this thought in the back of my mind that it's just all in my head. I don't know. Do y'all have any recommendations of what I could do to help keep my mind distracted, but in a good way? Or am I just overthinking things? Thank you!