Feeling down

Hi,

I had my son on Nov 21st 2016. I was 16 years old. I am now 17 and wouldn't change my son for the world. However, recently I've been feeling pretty down. Particularly because I see young couples my age, doing couple things, going on holiday and generally looking happy. These are a few things that aren't included in my relationship anymore. As I said, I wouldn't change my son for the world. However, sometimes I tell myself; maybe I shouldn't of made the decision I chose. And what I'm asking is, am I a bad mum for thinking that way? Because I really feel like one. Don't get me wrong, my son has made me a better person and he's taught me the true meaning of love. However, I feel like I'm missing out on so much.