Confussed???

I have 2 adult children and resently each of them have given me a grandchild. My son and I have had a strained relationship ever since he was about 16 and he is 31 now. For him if I have an opinion I have no right to it. I have come to live with our relationship that we have none. I still dont know what happen other then it was about the same time both my parents passed away. My daughter on the other hand we have always shared everything. She has always lived with me. When she gave birth to my 1st grandchild a girl I was there to cut to cord. I stayed with her in the hospital right by her side and helped with the baby. The dad was locked up in jail on drug charges. Since he has been released my daughter has taken my granddaughter and is staying with his mom and him. While at my house my granddaughter was gaining weight, happy, and developing very well. At her last well visit she has stop gaining weight, she dont seem very happy, and over all I am just not sure she is being cared for at all. My daughter has started lying about me, she snaps at me if I even open my mouth. She dont want me talking to family or friends about any of this or rather my feelings. It is as if she is trying to keep me from doing or saying anything at all. I am not sure if it is empty nest, depression, or I am just plain crazy. All I know is that I am worried about my granddaughter and she now takes it as an attack on her being able to care for her child. We have never been like this till she met this guy that is just plain bad for her and the baby. The dad and his family have convinced her that I am unable to care for my granddaughter due to medical conditions and that I use a walker to get around. It is funny though for the first 6 weeks for my granddaughters life I was there day and night to help, but now all the sudden I am not allowed to even see her for more then 30 minutes maybe once a week if I am lucky. I dont think I am crazy or have this empty nest thing going on. I just dont know what to say or do any more that I may loose what time I do get with her as little as that is. If any of you have the same type of things going on would love to hear what you think or have already been through this would like to know how yours turned out. I just really dont know what to do now????