I was doing a PhD in a different subject and that was going nowhere and I lost interest in everything that I was doing. But I always loved mathematics and during the dark days of my 3rd of my (former) PhD. I happened to meet some exceptional theoretical CS people who encouraged me a lot. One of them got me as a TA and I am starting afresh in this new field.
How optimistic should I be about a career ahead?
I want to be a researcher/faculty.