I noticed that the last upvote I received was worth only one reputation point. Is it because I have reached the daily limit or is there some other reason for it?
Yes. Once you reach 200 rep points on any given day, (with the exception of points from "accepted" answers), you are said to have "capped" in reputation for the day. You show 216 in rep on today (MSE time).
From what I see in your rep, is that the gain of only one rep point for a seventh upvote on a question may be removed, upon correction. From what I see, you have (or should have) earned 200 points from upvotes today, where meaning you have "capped", and 15 more points for the answer that was accepted today.
The only way to get more rep today is if one or more of your answers are accepted.