Just graduated bachelors comp sci. Didn't get into MS. Confused what to do I just recently graduated university with a bachelors in computer science. I did not participate in the career fairs at my uni,  because I wanted to apply for MS in US/Canada, even though everyone told me to have a backup option. Unfortunately, I did not get admit for any of the MS Programs I applied to. Now I'm not sure what to do. I want to apply next year again but I'm just afraid now.

My parents told me to get a job right now - but my problem is that I have really low confidence. First, not getting an admit really threw off my morale. And also, I'm really bad with interviews. I throw up before each one. I am very socially awkward. Even thinking about an interview makes me want to puke and gives me headaches and fear. Another thing is, I haven't had any revision/practice in almost 2 years - with the DS Algo OS DBMS stuff that they ask in the interviews. This makes me hate the technical interviews even more.

I'm thinking to take a gap year... revise my courses, practice interviewing by applying for jobs, learning ML from MOOCs (and maybe write a paper), and doing some volunteer work in the following year.

Will taking a gap hurt my career or my MS application?
Get a job. You write that you have really low confidence, are really bad with interviews, are socially awkward, etc. These are not reasons to not get a job. The point is that even if you had been admitted, you will still have to get a job after you finish your MS degree. Since you will have to face these demons eventually, you might as well do it now. These things may be scary, but they can also be conquered (see Workplace.SE for more advice). It can even be a blessing in disguise - you might decide that you'd rather keep working than go to graduate school. Remember also that the longer you wait, the less employable you become.

You could take a gap year also and do all the stuff you mentioned, but you would be spending money without earning it. That is not sustainable. Unless you are independently wealthy, you would be burdening your caregivers for an extra year. Your caregivers are likely much older than you (i.e. they need to think about their own retirement). Meanwhile you'd be spending one of the best years of your life on things with uncertain long-term benefits. Is that responsible behavior to you? 

You can't postpone growing up forever. Get a job.