"Sinnoh Stone not dropping for anyone else?"

#PokemonGO: First post, sorry if I haven't seen another post about this, but I've gotten 3 Dragon Scales, 2 Kings Rocks, and 2 Sun Stones, I've just hit level 24, I battle 3 times a day, I walked 88 Km a week, that's about average for what I do per week, and I've seen no Sinnoh Stones.​I've completed 3 weekly Researches to get Entei, Suicune & Moltres, still no Sinnoh Stone, am I just unlucky or am I missing something?​Living in Ireland. via /r/pokemongo http://bit.ly/2AfMeSL