You're just in a grieving process; it's natural to be moody& short tempered, so don't worry about it.
You just need to find someone like a counselor or teacher or friend who you can trust to talk to and let it all out. Feelings only have power over you when you keep them bottled up. When you release your emotions- through talk with somebody who cares and understands - you WILL feel a lot better.
You're not going through a breakdown; you're just down- which is normal. You can also go to a doctor who will see if you need medication. But most likely you just need to see a counselor for support.
You also have to keep out of your parents' battles and lives your own life- through friends, outings, and hobbies - as much as possible.
If you take this advice, you WILL come out of this bad patch and feel better. Pls find someone to talk to today and live your life.