Sounds like you've only got a few days left on your entry stamp. Why leave it until the last minute to apply for the non-O? You've run out of time. Get the 30-day extension and apply again
If you're only going to a border to get a new visa-exempt stamp it's a border bounce. if you're going to an embassy or consulate Inna neighbouring country it's a visa run because you're getting a visa. That's what it is, irrespective of what others claim
The authorities don't give a stuff UNTIL someone complains. And there's always a someone. It could be the "best friend" of your girlfriend, who is jealous because she has more money. It could be another farang who takes a dislike to you. It could be an immigration officer who doesn't like back to back border bounces. Remember if you are resident in Thailand for more than 180 days in the year, you are liable to pay tax in Thailand, irrespective of where the money is made. Sure, you get tax credits if you pay tax overseas, but then that means telling the authorities you're working in Thailand without a work permit. Advice I give is if you do it tell NO-ONE, and make sure you're on a legit long-term visa