“I forgive and forgive and forgive and then my heart will turn to sudden stone
then I become very angry and unforgiving which I hate “
That’s because you never forgave in the first place. Let alone forgave and forgave and forgave! You buried your needs and your rights and accepted shitty behaviour because something/someone drilled that into you. But, deep down, of course you didn’t forgive them. Because you shouldn’t. So eventually the anger surfaces.
You don’t need god/God, a minister, an Alpha course, a religion… you need a decent therapist.
The very Christian position of, “turning the other cheek” doesn’t actually mean let people treat you like shit. When God flooded the earth, he wasn’t turning the other cheek. When Jesus over turned the table of the money lenders, he wasn’t turning the other cheek.
Sounds to me like you were brought up to ignore your own needs, and with the Alpha course you tried to find a religion that would make you feel virtuous for continuing to do so, because it’s a lot easier than changing.
How would you feel at the Pearly Gates if you said to God, “I was super nice and forgiving and I’m here for my heavenly reward please” and He said, “I gave you this wonderful opportunity for a full and happy earthly life, and you squandered it?”
Therapy!