Total despair and not sure why...perhaps it is for being a mother this way...?

I have been very distressed for 2 weeks now. Weeping even in my sleep. I split up with my partner, or rather, we had a bad argument and simply stopped talking. I have lost a great deal of my faith in him; at least I need some space and time to think about the goods and bads, but I do believe that this relationship may be over. This saddens me, but I am in despair over my maternity. I have been a single mother since I was pregnant, as my fianc� left. It was very hard, and I felt very lonely not being able to share the joys of maternity. Xmases, Easters, holidays, teething, schooling, it was all painful in spite of me adoring my baby, because I couldnt share it with someone to love and be loved. Slowly I rebuilt my 'nest', and started seeing some new men, but I was never interested in letting them 'in my nest'. After 5 years of this, I met someone who made me fall in love very much, and he seemed very much in love. He talked about living together, and even if we did not, he was over at mine nearly every day and night. It all came very naturally for both of us. Now I believe that this relationship is over. He has disappointed me a lot, and even though we don't see or speak to each other since, not sure, perhaps 2 weeks or 3, I don't 'miss' him...yet I am in despair and cry all the time because I realise that I haven't adapted myself to this 'single mom' parenting. I cannot stand another weekend, another first day at school, another easter break, another summer break, all onto myself. Financially and in practical terms I am OK: I raise the child well (he is turning 6), I provide for everything, and everyone admires me. Yet emotionally, I feel extremely fragile, I feel I can't do the parenting on my own, I miss the emotional support, I seem unable to enjoy maternity and as I think this I get in despair and feel guilty towards the child. I really don't know how to get out of this! Someone says I am just morning for my partner. But I am not sure I am hurting for his loss or rather for the way I am obliged to parent my baby. Anyone any ideas, experiences anything that can help? Thanks!