I have a bad relationship with my mother, she has nothing positive to say to me or about me, but will mostly hold back from negativity towards me.
DS is 14, and lovely :) He is very sensitive.
Last year my mother accused me of neglecting DS by denying him drinks 
although he is a teen, is given plenty of drinks, and can easily access squash, water and hot drinks if he wants them. He does need some prompting. My mother was lucky lucky to be able to continue to have a relationship with DS and I. I did not tell DS about this accusation; there was no need to upset him, and since the accusation was borne out of malice and a need to criticise. My brother told DS that mother and I 'had argued' but urged DS not to believe everything he hears (from me). That put me in a position where I had to explain the situation to DS, while he had been forewarned not to believe my explanation.
At the time I made it very clear to my mother that her nasty attitude towards me will not be tolerated, particularly in our home. I also made it very clear to brothers that I will not put up with this.
Since then things have been as ok as they could ever be. Until this week.
My mother offered to take DS out for the afternoon and evening while I worked this week, which was kind of her. She then took some food items from my house which were defrosting. I looked everywhere then called to ask if she knew where they were. Brother answered and told me they had taken them because they had assumed they were my contribution. I explained that I did not know this arrangement had conditions attached, and that I cannot afford to give any food away at the moment. Brother got unpleasant (he has been very aggressive towards me over my refusal to be treated like shit by mother in the past, which intimidated me).
When mother dropped DS off later I asked for my food in a light hearted way, and was given replacements that they had bought. I thanked her. I was met with a barrage of sneering criticism about what I should be providing for DS but am not. I asked her why she feels the need to criticise me constantly and why she never feels she can praise me and recognise my successes. She started to leave, and I said she cannot criticise me in my house, and yes she ought to leave. DS ran off. When she had gone he came back in tears and said that since my phone conversation with my brother he had been really worried about everything.
I just cannot trust either of them. My mother has never liked me, has never tried to boost my self esteem, choosing instead to put me down at every opportunity. My brother backs her to the hilt, and can be aggressive in doing so. They are not able to hide this from DS, and make him feel awful :(
I also realise that DS was worried about my reaction. I am explosive when it comes to my mother, I just will not tolerate her nastiness and will bite back. I wish I didn't.
Both mother and brother have not spoken to me since, and giventheir track record are likely to make arrangements with DS without contacting me.
I feel the need to assert my position as DS' mum and protector. I need them to understand that their position in DS' life is actually conditional, and that they cannot compromise him like this. DS loves them, esp my brother and would hate to have this relationship disrupted, he fears losing my brother, and I think he would rather I shut up and put up in order to not rock the boat, yet hates their attitude towards me.
How do I move on from here? How do I find a way to manage this?
I'm sorry this is so long, but it is difficult to discuss this with family and my friends cannot stand my mother and talking about these incidents fuels this.
I would really appreciate some advice