I am 21 yo I discovered last year that I suffer from anxiety disorder because I went to get checked and a doctor and he told me "don't you get some panic attacks?" I said "yes" I told him that I have bad focus he gave me a GAD drug. After searching the net about what could cause GAD, I have found that traumatic events in early childhood could be the cause.  
As I remember, from the age of 6-14 I have been abused by my dad, and from age 6-10 I have seen some events where my mom got abused by my dad very badly he even Threatened her with a knife one day bcs they argued about my homework. When someone make a mistake me or my mom or my sibling just something simple, like one day my dad left the bread in the oven to heat up and he told me to take it out when it gets ready, my dad went to the toilet, I was busy doing something and forgot the oven... the bread got burned and that made my dad furious then guess what? he took his belt off and started hitting me with it like a savage like he was killing a snake or something.  
Another event happened to my mom where my dad made my mom bleed in her feet I don't remember what exactly happened but I still have and image of my mom's blood on the ground ( just some drops) and my dad when he is angry he just say bad things like one night he said "I will open this butane bottle and everyone will be dead by the morning" he said, and me experiencing the abuse and seeing how he deal with us made me always aware of him causing some serious problems to a family member (maybe even dead) and &gt;!till now!&lt; when ever my dad is near to me I feel insecure or yelling at   
 someone or in a phone call gives me fear and anxiety.   
And this has affected my school and my life in a bad way, I couldn't focus at school at university and this made me get bad grades, getting panic attacks when public speaking, exams or even thinking to talk with a random pretty girl that walks near by. this made me loses my confidence, always overthinking  feel extreme and unrealistic worry and tension — even if there’s nothing to trigger these feelings (symptoms of GAD).  
If you have had GAD and cured it please tell what to do because I can't live the rest of my life suffering.