Am having Suicidal thoughts?

I'm 26 and live on my own with my 2 little ones.their dad wants nothing to do with them and hasnt bothered to see them in 2years.i've got very little help from my family and am away from the kids about 1 night every couple of months.i havent got anyone i consider a mate either as ive pushed everyone away the past couple of years.my main problem is though the last year or so ive just felt so down and miserable ive thought about taking my own life.the only thing thats stopped me is that i love my kids to much and worry what would happen to them if i was gone but now i feel they deserve so much more than i can give them.all i do is shout and moan at them and theyve even told me that they hate me.i can barely afford to feed them properlly or keep a roof over their head that i feel theyll be better off with someone that can give them what they need. Ive even planned out how am going to it which scares me sometimes.ive tried to get for this with my dr and health visitor but both said theirs nothing they can do but give me a bunch of books about how to change my kids behaviour. I hate feeling like this and want to be the mum my kids deserve but i cant go on like this anymore.please if anyone has any advice or has gone through the same i would like to hear from you x