After undergoing surgery on a severe finger injury during Ireland's tour of Australia in June which ruled him out of the start of the season, the 2010 RBS 6 Nations star was delighted to return and begin making strides towards full fitness.
"I thought my lungs were about to explode, because I haven't done much running," said Trimble, who missed Ulster's opening two victories over Aironi and Ospreys.
"But I settled down in the second half. I felt pretty good and started to enjoy it a bit more.
"I'm not a great spectator. It's difficult watching, and actually more difficult when we're not doing well.
"It's frustrating when we are doing well because you want to be part of it.
"I just spent the past week doing a lot of daydreaming and thinking I just couldn't wait to get back on the pitch.
"The last couple of weeks maybe haven't been pretty but I think we've shown a lot of maturity in that when things haven't gone to plan we've been able to dig in.
"That's something we didn't used to do. Now we need to push on from there."