Daughter living with grandparents

[JustANumber]

I've been wondering for the past few days whether i should post this or not. I feel like a terrible mother who has bypassed all responsibility of my 5 year old daughter.
I suffer from clinical depression and have done since the age of 14. It reared its ugly head once more in January of 2015, I started taking anti depressants again and started to feel better. I gave birth to a little boy later that year and everything was going great, but in the back of my mind i couldnt help but think i loved him more than i loved my daughter.
I struggled with PND after she was born and the relationship i was in with her father wasnt the best, being 20 years old at the time i was naive and stayed until she was 2 years old. I left with my daughter and got my life back. I still didnt feel like she was my everything like you hear other mums talking about, i never got that rush of love when she was born. It never dawned on me how dysfunctional it was until my son was born and i felt how i was supposed to feel.
My son is now 8 months old and 6 weeks ago my daughter went to live with my mum and dad, it was their idea they said if i wanted she could stay with them for a while until i was better. The only thing is i dont know if i'll ever feel like im supposed to. My daughter came for tea the other day and she ended up going back to my mums after an hour, i was upset because she doesnt want to spend time with me. But i wasnt devastated like i should have been. My mum said if it came down to it and she didnt want to come home then in the long term she would be fine staying at their house. I dont want to cause my daughter any long term damage seeing me being depressed, but on the other hand i dont want to cause problems in the future. Will she think i sent her away? Will she have issues with me in later life?
Im sorry its a long post but i needed to get it out there, not sure what answers im looking for but im not looking to be flamed either, im feeling bad enough about this as it is.

It doesn't sound flame-worthy to me Op - I've no advice just offering sympathies, and wondering if you're getting any sort of counselling and whether you can discuss this with them? You're trying to do your best by both your DC, your daughter is being well looked after by your parents - give it time, feelings do evolve. I'm not sure there's a fixed answer to this question. If you stay living near her and she sees you and there's no mystery about who you are, you can always talk to her about these things. It's very often not clear what the best thing to do is so all I can say is look after yourself, i wouldn't read too much into one tea, don't let it put you off seeing her again.

My sister had a similar thing happen but for different reasons.
Her eldest ds went to live with his grandparent's whilst her 2 years younger ds stayed with her. Although I don't remember the exact age, it was primary school age.
That lad is 26 next month and to him his grandparent's are his parents. Yes, he sees his mum but to this day she doesn't have much time for him.
He is a lovely, well rounded lad with a good job and knows how to treat a girl nicely. He can also see that his mum did what was best for him even though it is unlikely they will ever have a typical mother son relationship.