Since you are already on medication for OCD, you surely have a strong understanding
of this disorder. You know your
fear of snails is irrational, but the OCD has the upper hand. For now.
It's my humble opinion that the medication is not working very well for you. Perhaps upping the dose or changing meds might help, but they will just mask the symptoms. If you REALLY want to get your life back, I suggest you invest your time getting therapy to deal with and hopefully overcome your OCD.