How do I know if I've made the right decision?

How do I know? This question has been bugging me ever since my move here. How do I know if I've made the right choice? It's already been a month here but I still feel like a fish out of water. Could it be that the last place I was in, the environment was so great and now over here, everyone's just minding their own business? And speaking to my ex-colleagues over the weekend, I realise that I really miss them and the camaderie we shared. It was amazing as to how fast we all just clicked and chatting away like we've known each other for years. And the relationship that I had with my ex-boss was also amazing and I think is almost impossible to find anywhere else. The dinner with them was great and I really miss working with them.

So now, I'm left wondering if I've made the right choice by choosing to leave to pursue this path I'm on now. Everyone says that it's the right move, the wise move, but is it really? The problem with me is that I don't know what I want. I don't know where I want to be in 5 years time. Sure, there are things that I say when someone asks me that question, but I don't know if that IS what I really want.

I keep thinking about what I had and if I made a mistake choosing to leave. I think it's mainly because of the team dynamics and what a great boss she was. If only someone could just tell me straight to my face that I made the right decision and that everything's going to turn out good.

Because of this change of job, I now have to move as well. Another change in my life. I don't necessarily have to move but the journey to and fro work is just horrendous. But the one thing that's holding me back is that, what if this doesn't work out? What if I do really badly at this and I need to find something else? I know that's like really thinking pessimistically but what if it really happens? I know that it won't happen if I don't allow it to happen but it's been a month and I'm still feeling awkward with what I'm doing. I suppose it could be that because in my last place, I knew everything at the tip of my fingers.

Oh gosh... this is so hard. I hate when I'm feeling so much doubt about myself. So, how do I know?