Is it the weather? Irish weather can be a bit depressing and takes some getting used to. But the winter won’t be as cold as in NY. And if you try to embrace the pub culture, nothing beats a hot cup of tea (or a pint;) in front of a nice cozy fire.
Or maybe it’s COVID restrictions that are adding to your misery? They have definitely been more strict there than in NY, but that should ease up in the next few months.
What about the other American kids in the dual program? Hopefully, you’ve gotten to know some of them during orientation activities, and you would likely have more in common than with the Irish kids.
I know it doesn’t feel like it right now, but you’re enrolled in an amazing institution (how about that library!?!?), in an amazing, very fun city with an international population, in a gorgeous country, with easy access to many destinations in Europe. It’s such a unique and special opportunity that you’ve been given! I think that if you are able to talk to a therapist/counselor and get through this period of adjustment/homesickness, you just may love it. Also, I think that you may start to feel more positively about the major you chose once you feel more settled and happy in your situation.
Lastly, don’t make any decisions based on what others think. Do what’s best for you.