Worth a call to the doc? Yes, absolutely as your current medications should've worked by now. Our most stubborn and hard to treat inflammation is always within our rectums. Just because you have proctitis doesn't mean you get an easy-pass.
I'd take your prescribed medication while away, and I'd set my alarm early to take care of your bathroom trip before others awake. That's what I do in this situation, it's common for me to stay with my in-laws out of my state for holidays like xmas or thanksgiving. I'd often be last in line for the bathroom in the evenings (after others have settled in for the night). An enema is quite easy to conceal within a pocket or purse. As long as you close and lock the door, nobody will be any wiser that you've taken it. If the bathroom has a fan, turn it on to conceal any noises. I set my alarm on my phone for 6:30am and use the bathroom while others are still asleep. It'll be fine, I've done this numerous times, don't worry so much