Sending automatic emails dependant on date in a certain column

Hi,

I am looking to automatically prompt emails dependant on what date shows up in column P (Needs to be 2 weeks on from this) but to stop it constantly happening if cell Q is populated it will prompt on that column instead. Once it has prompted once it shouldn't happen again. I hope this makes sense, just ask if it doesn't.

I have filled in the form to give you more of an idea. Contact 1 is when I first contacted them and how.

First Name and Last Name are where the name goes. If you think other fields need to be added then please feel free.

I have attached a spreadsheet.

Thanks in advance.

Danny