I have never felt so let down and betrayed

I worked for a company for twelve years from the most junior position up to a very senior level. I worked very long hours and was very, very loyal. Every yearly review I was told I was doing a great job and given a healthy bonus. I Got pregnant. Just before coming back after five months maternity leave, I was taken for lunch to be told they had coped well enough without me in my position so I could come back but without the title. I was shocked but I thought – well if the money is the same, then maybe I would be better without so much responsibility. Few months in: bonus due. (These bonuses were consistent and mine had been the same for several years) this year mine had been cut by 75%. So within a few months of returning I had lost my position and had earnings cut so that I was effectively back in the job title and salary I had been in seven years earlier. I left. I have never felt so let down and betrayed as I had loved my job. With what was left of my tattered self esteem (obviously already pretty battered after getting lost in new baby world) I mentioned the word ‘tribunal’ and almost immediately got a lump sum pay off. Not a lot. Basically the bonus I should have got. It’s a small industry so we are polite when we meet and I am very successful at another company but it will always be the single most professional disappointment of my working life. I never thought it could, or would, happen to me.