The best way to overcome this is by going further out of your comfort zone and actually speak up. That's why we have challenges such as these, so we can overcome them and grow as a person because of it.
I would attempt to contact her and make it known you are making amends for your actions, you will find she will be more inclined to actually let you talk to her because you are accepting your actions were out of hand and are truly apologizing for how you acted.
Asking for help is actually a show of strength, it is hard for anybody to accept they struggle with something and ask for the help they need.
It will be hard, but as is anything that makes you grow as a person.
No one generally knows what to say in those situations, which is why it is a good idea to have a think about it and even write out an apology as it will go along way to help with the worry of saying the wrong thing.
We have all hurt someone and I have attempted to make amends, sometimes it works and sometimes it doesn't, you won't know until you try and at the end of the day it is up to them whether they accept your apology or not.
Even if they get upset or angry it is still creating peace, you may feel like crap(and probably deserve it) but in doing the right thing you are at least being at peace with yourself which will allow you to move on with your life.
Just "Bottling and deal" is actually incredibly unhealthy and as you have seen leads to some un wanted consequences.
It is also worth mentioning that you have nothing to fear about opening up to complete strangers(especially when they are there for similar reasons), hell you know you are doing it now right
