I think every action counts. So that 5 minutes is better than 3 or 0. If you want to build the habit that’s enough. Otherwise, listen to yourself & if, as you’re saying, in 5 minutes you are not in the state of mind that you desire… It’s time to level up till you’re on point.
I've never meditated for just 5 min, but I can just imagine how you feel. After just five minutes (of 15-20 total) all I feel is my breath more relaxed and my mind less stressed. But I don't feel like I've really meditated and became more self-aware nor mindful nor anything. So yes, I do recommend you to meditate for a longer period of time. Start with 10 min.