Have said I'm suffering with PTSD.. Could it be so considering..

Basically, I've been sexually abused 4 times in my life.. 3 of them rape, only 2 of them reported and one of them my adoptive brother sexually abusing me, never actually having sex with me, so not actually raping me.. Right?

I now have an obsession over checking that my curtains are closed before it gets dark, that my window's shut, my expensive equipment (guitars etc) are away, cupboards, drawers and doors are shut. I get into bed feeling ok, then a sudden panic grips me and I have to check the door again and again before I can sleep.. It's my first night back at mine tonight, after a week away. So far I check my door about 5 times.. Which, to me is starting to get worse..
I'm so stuck and confused.. Constantly looking over my shoulder, checking that no-ones walking behind me, constantly making sure I'm not attracting any attention.. The last rape was only about 3 weeks ago and so far I've heard nothing from the police.. Im terrified.. What if, as people living here say (one of them a witness-who lied- and one of them a friend of the witness), they're all out to get me and are going to come and jump me, or get someone to rape me deliberately? i don't know, I'm panicking and I don't know what to do!

And I have had a really crappy family life.. I have an alcoholic Mother, my Dad is dead, he hung himself from too much stress when I was one.. I was then put into foster home and stayed there until I was 5, then when I was just turning 6, got put into an adoptive home and it all went downhill there too.. My foster home was the only place I felt safe and loved.. I was then sexually abused by my adoptive "brother" at the age of ten and all this time, from the age of 5 up until I was 16, I was emotionally and physically abused by The Adoptive Parents.. All the while, my twin, the more naughty, loud one, got away with murder, she got so drunk, she got into a huge fight, brought home in a riot van, passed out on the kitchen floor..

What would any normal parent do? Say "I'll ground her for an absolute minimum of a week and have a curfew set for when she does go out. IF she does.." OR "Oh I'll talk to her tomorrow and if she screams the house down and bawls her eyes out, I'll let her go out, with the curfew of 10pm"?

They chose the latter. Then, took the p*ss out of me when I started SI'ing. Seriously, screamed and laughed in my face, telling me to "go slit my wrists and bleed to death". That was when the SI got worse and the self esteem and self respect and confidence faded completely and depression really kicked me in the butt.. On top of this, since the age of 6 I'd always been a slow eater and not eaten much, so when I was ten, started eating less and less until it came down to nothing at the age of 12.

Could this be PTSD?

Help?