Hi Maysun my friend

I suffered from very strong Panic Attacks and Fear form sleeping and Paranoia from walking on a street at night, well Paranoid I was very much we might conclude. Just recently I got diagnosed with PTSD (war combat and crapy childhood).
I will try and share my experience by drawing inspiration from what you have written:
Under your practice in the side bar you wrote;
I have no idea really, try a bit of everything
I joined this community back in March 2010 I think and was in search for a meditation technique which will calm down my anxiety, panic attacks and paranoia.
I got offered here to try a technique called Shamatha or Calm-abiding (artice is on the front page). I started practicing this technique with whole of my heart for almost year and a half and the result was fantastic I must say. My Panic Attacks, Fear from sleeping and walking on the street at night as well as my stif neck pain have subsided drasticly and thanks to that I can function much better in my every day life.
It took me about 6 month of daily Shamatha practice to come to that point. I practiced 40-45 minutes every morning, at times even two times a day. At work I would make sure to go to sit in the toilet for 5-10 minutes and this would calm me down during working hours.
However, it seems right when I find out what works, my mind starts sabotaging me, doing the exact opposite
When I started with practicing Shamatha I experienced exactly the same phenomena as you describe here. What you are describing is not to be taken as a failure but the very truth of our reality. What you are describing is the very First Noble Truth of The Buddha

"Life Is Suffering" or the way this mind of our clings to phenomena that is.
You are doing great in my opinion, the only small tiny thing I would suggest is to always base your practice on Calming the body with each in and outbreath.
Restlessness is one of the 5 Hindrances which are to be calm down/let go of.
I am only feeding on my frustration or fear and end up way more frustrated than I began
I can totally relate to this. I too got as frustrated as you. What I got to do is follow the Shamatha instructions closly, this is also what the Buddha instructs; Be Aware of the Arising Phenomena, Comprehand it Clearly ("feeling of fear and frustration"), Calm this phenomena into the body with each in and outbreath and gently once calmed return to the Object of meditation (in this case breathing).
This worked for me like a charm.
I´m trying to accept and let go of every thought but trying is not the same as actually letting go
Most if not all practitioners get this very same issue

I still ride that horse

Thoughts will be there most of the time it is the way we RELATE to them that COUNTS

Here is where you get the Insight into the nature of Suffering The 2nd Noble Truth "Clinging to phenomena causes Suffering". We cling to the arising phenomena by feeling Desire or Aversion towards it. We Desire stillness and silence and calmness and we feel Aversion towards the invading thoughts, unpleasant bodily sensations and emotions. All these Arise in within the body and right here you remedy this by Clearly Comprehanding the arisen phenomena (pleasant or unpleasant), Calming the body until the phenomena Passes away and returning gently to the Breath or the Object of meditation. This is the way of ACTUALY Letting Go (The 3rd Noble Truth)

and not by pushing it away

which is based on AVERSION

and DESIRE for something better (2nd Noble Truth).
I made a song called The Four Noble Truths Unplugged which you might find useful. It is made in a funny way but still it does bring the message across I feel
http://cheguebuddha.blogspot.com/2011/12/four-noble-truts.htmlp.s. If you want you are more than welcome to practice with me once a week over the Skype. This community sits together over Skype video conference once a week. PM me if you want my skype user name

May we all be happy