The next day, we hired a cab from Pattaya to Bangkok airport, from where I had my flight back. A one-way cab would cost you around 1500-2000 Bahts, but is a good option when you have a lot of luggage and shortage of time. Otherwise you have the buses running all day anyway.
So that was my first international trip in a nutshell. Great experience, a lot of fun and some learnings as well. Looking forward to making many more of them, and not stopping anytime soon!