The plant you tried
may have had more THC (the chemical that induces "highs") than CBD (the chemical that treats pain). Some strains are now being bred specifically with low THC and high CBD.
It
appears that, as in some other countries, while cannabis/marijuana is illegal in Ireland, hemp is legal (even though they're the same plant). Some here (review the thread) are looking into hemp oil, which may contain the CBD for pain, without the THC. I don't know if this is an option for you, but I think it's worth looking into.
http://hempworld.com/Hemp-CyberFarm_.../irelandh.html
hemp in ireland
Doc