Does my 90-day notification period start from the day I got stamped in after returning to Thailand?

Thanx for the update, we always tell people if no one is at the counter, find an officer and they'll get someone to sell you a re-entry. Glad it worked out (y)

make sure you check your entry stamp to see that you were stamped in correctly (with a re-entry permit) and not by mistake on a free stamp entry

𝗱𝗼𝗲𝘀 𝗺𝘆 𝟵𝟬-𝗱𝗮𝘆 𝗻𝗼𝘁𝗶𝗳𝗶𝗰𝗮𝘁𝗶𝗼𝗻 𝗽𝗲𝗿𝗶𝗼𝗱 𝘀𝘁𝗮𝗿𝘁 𝗳𝗿𝗼𝗺 𝘁𝗵𝗲 𝗱𝗮𝘆 𝗜 𝗴𝗼𝘁 𝘀𝘁𝗮𝗺𝗽𝗲𝗱 𝗶𝗻

Yes it does 🙂 your next 90 day report is due 89 days from the date you stamped in to thailand.