After having gone to Ireland several times, here are a couple things you should consider having with you. 

A good rain jacket. No one goes to Ireland for sunny weather. It’s not that you don’t see the sun, but rain happens often and sometimes it can happen quickly. Having a raincoat tied around your waist is an easy way to keep from getting too wet when it comes down in droves, or even just a steady mist. I recommend a jacket I got from REI. It has kept me very dry, and it is made with a liner. The rain that comes down in Ireland is usually cold. Additionally, sometimes the rain jacket can help keep you warm if it has a liner. This rain jacket fits easily over a sweater if you need extra warmth. Don’t forget it anywhere if you do wrap it around your waist. Spoken from experience.

An Ireland/UK power adapter. So Ireland’s electrical infrastructure is left over from the occupation. It does not share the same power setup as the rest of EU. I like ones that allow for multiple plugs and different USB inputs. The one I have also packs easily. 

A good pair of walking shoes. I have nice athletic shoes I wear for this. They keep water out as well. I will not sacrifice comfort for fashion. Sue me. Plus, if you find yourself hiking somewhere, you will want a shoe that grips the ground well.

A wool sweater or pullover. This is essential. Wool also keeps you warm if it gets wet. Frankly, I think I look great in a sweater. In many cases, you don’t need a jacket, but a sweater will give you that extra warmth you need.

A note about euros. So I am going to do something different for this trip. With the exception of about 20 euros I have leftover from an earlier trip, I won’t get any currency until I am there. Avoid airports and currency exchanges. Use your debit card to withdraw from bank network ATM’s. They don’t charge ridiculous fees. It is IMPORTANT to let your bank know that you are traveling in advance so they will not flag the withdrawal as fraudulent. Most places you will spend money will take a credit card. Use your credit card for everyday purchases, not a debit card. Those are the best exchange rates.

I won’t make medical recommendations since that’s unique for you. Let me know if you have other suggestions.