How to know if one is suitable for pursuing academia or Research work their entire life?
So you are going to finish your PhD soon and you are thinking about what to do?

I understand your regrets, but they don't help you (as you probably know yourself). 

The question remains: What are your options now?

First of all, you do not make a decision for your entire life. You can start a research position and leave it after three years, it is not really helpful to try to plan for 30 years of more. You can either try to get a research position after your PhD, and if you get one, decide again after two to three years. Or you can look for challenging positions in the industry. Both approaches are entirely sensible. 

Just don't consider leaving academia as a failure. Most people leave academia sooner or earlier and many find an interesting, good job.