I think you can relax since it is between gdax and coinbase. Usually a transfer between gdax and coinbase is done instantly like you've probably experienced before, now there's probably just some delay/tech issue within coinbase and it is all logged in their backoffice for sure. I understand the frustration and I would be concerned as well, coinbase need scale up their customer service as much as possible to handle the absolutely huge amount of new customers they get on a daily basis, but I guess they are doing this already. One thing you could do is to write to them on twitter too.
Good luck with your issue here, I think it will be solved soon!