You first may want to consider overcoming your guilt with the help of a therapist. The act of discussing your feelings out loud may be an important step.
Indeed, they are far better trained for this than anyone here.
IMO, as someone in the field, this thread should've been closed after those posts.
But since it wasn't...
If the incident is significantly interfering with your ability to function in everyday life, then by all means, seek professional help.
1) Seek it not just for yourself. The whole family should be involved, as this affected the family. My guess is, this was more devastating to your parents, especially your dad.
2) Don't necessarily settle for the first therapist you go to, just like you wouldn't necessarily buy the first pair of shoes you try on. For therapy to be most effective, there should be a "proper fit" between therapist and client. The fit will feel right; you'll know it when it happens.
Good luck. Hold to hope, love and each other.