Not sure how many Irish people are here, but just in case...
In Ireland:
-During office hours-
GP - You can call reception and ask to speak to your GP, tell them it's an emergency. Most surgeries have a time in the morning that you can turn up without an appointment if you urgently need to see a GP. You can find this out by asking your GP or the receptionist.
Psychiatrist - Most of the time it's difficult to get hold of your psychiatrist right away. However, if you call their secretary, and tell them it's urgent, they'll get your psychiatrist to call you back.
Community psychiatric nurse - If you have a psychiatrist, you may also have a CPN. If you call them and let them know what's going on, they can come out to your house to see you, meet you somewhere, or contact your psychiatrist for you.
If you have a therapist or psychologist, you can also contact them, but if they think you need medical treatment, or psychiatric admission, they will contact your psychiatrist if you have one, or call the emergency services.
-Out of hours-
Emergency GP - You can find out where this is and how to get hold of them either from your GP or by doing a google search.
A&E - Obviously, if you need medical treatment, you should go to A&E. However, even if you haven't self harmed, you can turn up at A&E and ask to speak to a psychiatrist. There's usually one on call at all times.
If you need urgent care, and cannot get yourself to A&E, call an ambulance. You can use either 999 or 112 to contact the emergency services-Helplines-
Samaritans - 1850 60 90 90. You can also contact your local branch directly. You can find this on
http://www.samaritans.org/talk_to_someone/find_my_local_branch/ireland.aspx.
1life Suicide Prevention - 1800 24 7 100 or text HELP to 51444
I hope this helps