"Been searching for a Ditto for weeks, getting close to losing my mind"

#PokemonGO: Ive been impossibly stuck on the 5th set of the A Mythical Discovery special research tasks for like a month now.I have caught dozens upon dozens of every single possible Pokémon at every time of day in many different areas and nothing.I’ve watched youtube, read articles, generally gone to pathetic lengths to find that stupid jellyIs there something I’m missing?? Is the spawn rate really that low?? Where the fuck is that bitch ass I’m so sick of cleaning out countless wormples, gulpins, pidgeys, rattatas, etc i grow so wearyPls help how can I get this over with via /r/pokemongo http://bit.ly/2MIPsTK