I have a few ?'s and things you should consider to actually be more advanced than the other guy on Friday.
Is he (the pro) actually teaching you anything or is he just teeing off on you?
Does he let you "lead" some times..etc. and is there an actual boxing coach around to critique?
If he isn't letting you lead...tell him to let you lead for a few rounds and he just defend...then tell him to counter to your head a few rounds..then your body...then go full....and vice versa (he'll open up more about what you are doing wrong and what you can try..etc)..this is how you learn boxing...not going in and getting broken in to be a punching bag.
From my experience with so called "pros" ....they like to lead in sparring most of the time and/or lay back and land wicked counters to show they are in charge. Most don't know how to "turn it off" either.
It may not sound like much, but the guy on the other end never learns how to lead or take control, get his shots off, find his range..etc,etc b/c he's constantly worried about the incoming and return fire thus you'll "shell up" on defense when you should be deploying counters, slipping..tons of stuff.
You will be fine if you turn it into a learning session (even though you are not planning to do this long term) and not allow it to be a one sided beat down.
We have firemen and cops who come in and try to spar every so often just for their charity events and they all do the same thing...want to put on the gloves and spar....99% of them don't even know how to defend or throw a basic jab. 
Lol I know what u mean. When I'd been boxing only a couple of months I had to get in the ring with a pro who was 3 weight divisions higher than me. The other newbies ddnt wana spar him. I didn't mind, and wasn't in the least bit intimidated....as I didn't believe he would actually
try and hurt me!!
...how wrong I was. His first shot was a lead right that dazed me. He backed off for a bit, and I thought to myself, "my left hand is a bit tasty, I think I can land it. He countered with a bodyshot. Winded me. I was embarrassed as hell - although I had nothing to be ashamed of!