Maybe I'm just paranoid because I'm very careful around school buses (several schools are located close to my home), but I was surprised by this situation. A school bus was slowing down and I came to a stop because their yellow lights were flashing. (I was on the opposite side of the road from them). The driver made eye contact with me and waved me through and I passed by (I was on their left). They deployed the red stop sign when I was already past them. Can I still get in trouble for this? Again, I could be paranoid and I also didn't have my dashcam on me because it ran out of battery life.

Please let me know what I can expect from this. I apologize if I sound like a moron. Thank you!

It sounds like the driver was letting you through by withholding the stop sign. When you stopped, he waived you through rather than making you wait (maybe it's a busy drop off point.)

You don't have anything to worry about.

Thank you so much!

If you take a close look at the HTA, it is not only the side-mounted stop sign that requires you to stop for the school bus. You must stop when the overhead lights are flashing, regardless of the stop arm. This is under HTA 175 (11).

So technically it sounds like this 'wave through' scenario could have resulted in getting ticketed, regardless of the hand signal of the bus driver.

Regardless, the OP indicated that the yellow (i.e. hazard) lights were the ones flashing.