Welcome to maintenance! It's a different phase than you've been in for the last 6 months or so. You have done extremely well!! Everyone loses at a different rate, and guys lose faster than the ladies anyway. Enjoy where you are!
It's not unusual to have your weight move around a bit. It's actually unrealistic to expect it to remain at one fixed number for any length of time. Mine fluctuates +/- 3-4 pounds, and at my 4-year checkup this week the surgeon was very pleased with where I am. The "goal" number is arbitrary anyway. Your body knows where he wants to be, and he'll stay there as long as you don't fight him. Over the next year or two you may put 10% or a bit more back on. I bottomed at 159.
Worry too much? Well, considering you've never been here before, I'd say you're just trying to find out where you are and what's happening. Your reflexes are tuned to losing weight, and they need recalibration to this new phase. I see it more as curiosity and concern than worry.
Don't sweat it. You're where you need to be, doing what you need to be doing. Just keep following the rules. Look for weight trends, not short changes. React to the trends by adjusting your healthy intake. Ignore the daily fluctuations.
Good luck, brother!
CT