Worked 6 years for UPS in Doraville, GA.
Chances are you're going to stay, especially if you left on a good note which it appears you have and yes SOME seasonal employees are asked back after peak. I would still look around for other oppurtunities just in case, but from what you're saying you sound like a shoe in. If you don't hear anything after peak, call them. After 30 days means you have made seniority, not that you're in the Union. You have the oppurtunity to join the Union usually during orientation or Cornerstone Training. Union Stewards will also be an option.