@BlueBay
There is absolutely no need to be sorry for writing what you have - it shows immense courage to dig down deep inside yourself and expose your innermost thoughts and feelings to others.
Sometimes when things seem to be going ok we wonder when it will end - as it seems that every good thing in our lives have been followed really quickly by something 'bad'. This is what I call 'the pattern of my life'. So it is inevitable that the negative thoughts enter my head directly after something nice or good has happened as this is the pattern and behaviour that I have learnt from childhood. I suspect this is very simialr for you.
...the little girl is still inside you reaching out for help and support and knowing that it isn't coming from where it should be - your family. You search and yearn for that comfort, support and help and reach out to find it anywhere you can. You do then get attached to those who support you as a replacement for the 'family' that hasn't. In a sense, these people replace 'your family'. This I believe is a natural reaction to the losses you have felt and the need to be nurtured - something that was never resolved for you as a child. If one is not 'allowed' to be a child and the needs of a child are not met through each of the early developmental stages then later in life they do not have the appropriate skills to deal with such massive issues as you are dealing with.
Bear with me here - if you can - I am going to address each of your 4 points separately (from my persepctive...)
1. get back at myself for not being a better person
You 'learnt' from an early age that your were worthless and could be used and abused by many people - this stays with you your whole life as instead of being able to live a carefree and happy childhood and feeling wanted and loved, you have endured pain, hurt and humiliation from adults who should have been your protectors and not exerted their power and control over you to make your feel like a 'bad' person
...so you are not a bad person - it is just circumstances (and 'people') that have constantly 'put this thought in your head' to satisfy their own sick and deluded existence. As with any learned behaviour - it has been re-inforced over time by many people and the little girl inside of you has gradually started to believe it and accept it as fact - IT IS NOT.
2. to get back at my parents, to show them how hurt I am and make them feel guilty
To be let down so badly after disclosing such pain by your parents - your mother in particular - is not only unacceptable but heartbreaking. To know that you weren't protected when you were young and then to be so aggressively dismissed when you 'told' what had happened, tears your heart apart. It is hard enough to go through what you did but to then know that those who raised you and were 'supposed to' love and care for you turned the pain to themselves and dismissed where you were 'at' would certainly make anyone want to return that hurt. Do not feel guilty for this - the guilt should lay with those (parents) who did not protect you, care for you and then support you - unconditionally and without a thought for themselves - both as a child and as an adult.
3. to seek help
You seek help because you need help - it's as simple as that my friend...
4. a cry for help
When you have constant negative thoughts and feelings inside and you do not know how to deal with them you do cry out for help - again - it's natural. This is your way of trying to cope with unimaginable hurt and pain for you. I don't see it as a cry for help - but as a way to ask for support to get you through the tough times - sometimes all so consuming that you cannot see the way through.
I understand that you feel that you are scared to get 'better' because that would also mean that what has happened to you - and moulded you into the person you are - would also no longer 'be there' - that in essence you would lose 'who you are' - does that resonate with you?
I believe that your 'need' to attach yourself to your support people is in a large way the result of being abandoned by your family - where else are you going to receive the support, care and sense of love that you have lost - that is a massive thing to happen in your life and you are doing what you need to do to fill that huge gap that has been left. Over-reliance on 'some' people can also lead to being 'let-down' but if it fills that gap in the interim then that is what is needed to help you move forward day by day.
Inside you there is still that very hurt, very lost girl who has had her world turned upside down and had to deal with it on her own. You are still that lost girl but you are also a very strong, capable,compassionate, sensitive and resilient women - you have had to be to get through life and to achieve as much as you have. Tears should flow for this girl - as so much was denied her and she endured so much pain that no child should have to - and tears also flow for you - for the little girl trapped inside you and for the wonderful woman you have become despite what happened to you.
I am not only sitting on your should today but also sending you part of my heart to help heal that part of yours that is in pain 
Sending you all my love @BlueBay
Zoe
