Feeling irritated by everyone. I do?

I am a mother of a 2 year old boy & stays  alone with him as husband works in diff city. From few months I am feeling too much depressed & can't handle emotions..Even for slightest mistakes if any1 points it out , i will start crying.I feel I am left alone and no one care for me. My son is taken care by a maid and I feel that only I am burdened with his sole responsibility , no one else is coming and helping me out ..Neither my family nor my husband family comes and take care of their grand child ever.Some times I think may be I behave unusual so I am left alone but what I actually think since they all have deserted me so I am behaving so.I know that's by I don't want to behave well with them. They would only come when there would be super emergency like my son was too much ill once. I have a 10 to 5 schdule and I am not left with too much energy but still I take my baby out for walk and try to play with him. I am worried my health might hamper my baby development.  What should I do?