You poor darling! I know that feeling where it all gets too much and you just want it all to go away I have been there myself many times. Do you have any particular feelings about mediaction if it is depression ? I am on anti dperessants and found it really helped with that hopeless feeling where you just feel like you are trapped under a thick black fog, it won't cure everything but it helps.
Its such a shame your mum is no help, mine was my lifeline with the 2 girls, I have found it so terribly hard with Riley now that mum's not here.
Please let someone help you if they offer, its so hard to do but it WILL help. Let Amy come over she is very calming when you feel really bad I know from experience