Need advice/help

I am hoping that I can get someone's opinion on how I should handle a situation. Suffering form bipolar and pretty bad anxiety it is not a good mix for using good judgement at times. Well, I did a really stupid thing and now I regret it and wish that I could try to make it better in some way. I've had an issue with my next door neighbors for a long time. They are pretty inconsiderate and we've had issues where they come on my property, caused a bit of damage here and there but nothing serious. The biggest thing has been that they will not even do the basics like mowing the lawn. Knowing that they bother me there are just little things they do just to be jerks. Well, on one of my less than rational days I flipped them off. Needless to say things have not been good, and neither has my anxiety. I really want to apologize, but have been told that I shouldn't bother because it is going to make things worse and cause a confrontation. I know there is the risk of that, but i really do feel like I should apologize. Does anyone have any advice? If it is causing me so much anxiety would it help anything to apologize? I am afraid that they are going to be much worse in the future.... I suppose this would seem like a minor thing to a lot of people and they wouldn't worry about it... of course I just keep dwelling on it. Thanks for anyone's thoughts.