Hey there,
I completely understand, I struggle with contamination OCD related to health and people. Starting ERP can be a daunting journey for most of us at first. I would recommend two things:
1. Speak with your therapist about your "fear hierarchy", starting with smaller more manageable fears can be helpful when starting exposure therapy in order to teach your brain you can handle these situations. Sometimes if we are way too flooded initially, our brain's fear processing center (the amygdala) kicks into overdrive and it doesn't feel like can learn much in those situations.
2. Do exposures which help you realign with your values system. If you have not already started, type out some values that are in line with your beliefs. It can help to create exposures around these values and they can give you even more meaningful results. For instance, say you personally value kindness and compassion for others, touching a doorknob just because you consider it contaminated will not be as effective as holding the door open for someone else.
Hope these help and best of luck!