Do I have PTSD from child abuse...?

It's hard to describe if what I went through was child abuse or not. My parents really do love me, and I know that. However, coming from a traditional and conservative Korean family, it's obvious that they've beaten me countless times.

One flashback image that I never forgot was of one where I was I think around 9-11 years old. I don't remember too much details but ultimately it was my brother hitting me and I cried. I ran into the room to tell on him (yeah I was a rat snitch back then) and the next few minutes went by in a flash. I got punched consecutively by my dad. I've had worse beatings because this one wasn't painful, but rather numb. However, this specific image I still can't get out of my head. I am 20 years old, about to become 21. When I ask my dad about it sometimes, I feel awkward but the answer he gives me is that he doesn't remember that or he never did that. It could be true, because I only really remember this because I used to have nightmares as a kid. I know how PTSD is often triggered from releasing certain hormones during the "fight or flight" adrenaline rush... but I had no incentive to fight against my dad or even run away. If I ran away, my brother probably would've taken a big beating for "giving bad influence on his little brother." There were also constant times when my brother would put the fear of God into me when we were young and my parents were at work until midnight. We didn't have much money when we first came to America and often times I had to submit to my brother as my parents would come home past midnight. I took a lot of beatings from my brother as well... but I love my brother more than anything now.. The way I look at it, he raised me from kid to now. Every now and then, I have flashbacks about the beating from my dad or my brother holding a kitchen knife on me when we were kids. I never really "re-live" these moments but it's a really strong and persistent flashback that comes maybe every other day. At least once a week. All I know is, during that specific traumatic incident, I remember feeling extremely helpless, scared, and thought the skies were falling.

Here are some things that made me believe I might have PTSD.

-I feel disassociated from the world.

-Easily irritable (I wasn't always like this. I used to be extremely nice and friendly.) I shake my legs all the time. Every little noise catches my attention. I am jumpy when I used to be a laxed out person.

-I have extreme anxiety problems. I can't trust my closest friends because I always suspect them of something more elusive.

-I prefer to not talk unless spoken to.

-Except work, I often have to force myself to be able to socialize with people and it's exhausting. I like to go out and I like to believe I at least used to be outgoing. But to actually socialize with other people, I think my tempo or rhythm of the conversation is off.

-I always try avoiding fights now with my family. Even if I have an opinion or argument, I just keep shut and listen to them just so I don't have to hear people yelling. They haven't hit me in the longest time though. Now they use guilt-tripping and call us a piece of ****.

-My dad used to tell me how when he beat us, it was our fault and not his. We made him angry because we didn't do our homework or got a bad grade. When I talked to the school faculty at the time in around 3-4th grade (because we had to get them signed by our parents) they just told me to try better next time. They didn't know I was in for the beating of my life every one of those nights.

-The topic of child abuse certainly doesn't make me angry or anything. I feel numb most of the time. Like I'm not alive. One thing I definitely feel is discomfort. I always tell myself if I have kids, I will never hurt them like that.

-There's been thoughts of suicide but I truly believe suicide is for cowards or the easy way out. Thoughts of suicide is very rare.

Now, I'm at a loss. I'm at a point where I can barely communicate with my parents. I can't really talk with my friends because it's all forced. All I really want to do is just... sit and do nothing. Not moping around but literally just sit there and do nothing. Many of my previous friends think I'm weird or strange. I see myself being socially awkward many times. I want to go skydiving, play basketball, go to concerts, go mountain climbing, experience life. Even till this day, I don't because my parent's found a new form of abusing me. Guilt-tripping me. Especially my mother who's somewhat ill with possibly the beginning of Alzheimer's and maybe breast cancer even if it showed negative.

I live my life currently in constant anxiety, (I wouldn't say depression but some lines of depression), extreme frustration.

I've done several drugs before in my life, few of which I've gotten heavy with a