Graduate Admissions and Earlier Programs
First of all, I'm sorry for your painful experiences. To answer your question:

Based on my extensive experience directing a graduate program at a leading public R1 university, your initial experience in the initial program will have very little bearing on your chances of admission. I say this for a number of reasons:


We are concerned with trajectory even more than overall grade point. I am relatively unconcerned by someone who gets C grades during freshman year, so long as I'm seeing A and high B grades by junior and senior years.
When a student goes to school for a couple of years, then does something else for a few years, and then returns to school, I consider the grades subsequent to return almost exclusively. In most cases, unlike yours, this is because the student needed time to grow up. But I'm happy to accept that he or she (frankly, it's usually a "he" that fits this pattern) has grown up and to accept the high marks after the return to school as ample proof. I don't care what somewhat was like as a 19-year-old, I care what that person will be like in my program. 
You can and should explain the switch of programs in a graduate application. Having a letter-of-reference writer explain it as well would be a wise move. Once an admissions committee sees the highly valid reasons, there is little chance that they would hold your record at the first institution against you. 
Everywhere I've been, if grade points are used to prune or order applicants, only the gradepoint at the final undergraduate institution is used. This may not be universal, but frankly I find it unlikely that most graduate admissions programs would go to the trouble to compute the proper weighted average across programs, even if they did care about your earlier performance.


I hope this is helpful and perhaps even encouraging.