joint pain

I'm 30 weeks pregnant with twin boys. I have pain in most of my joint. I have to use a cane to walk. The pain is great. When I wake in the morning it feels like my fingers are not completely in the sockets. My left ankle has felt sprained for well over a month. If I walk around for a hour with resting every few minutes my feet swell, double in size.I'm getting worried. I have fallen twice this week because my legs a shoulders give out due pain.Has any one had this happen or heard of this happening. I just want to be able to hold and care for my babies after they are born.