Anyone have experience with Namenda for just age-related dementia?

After a couple of difficult weeks, a trip to the ER, we stopped the med. MD seems to be treating this as Alzheimer's. NP who gave us diagnosis seemed to know nothing about types of dementia, but told us this wasn't related to Alzheimer's. Then for info, she gave me 2 books on Alzheimer's. Meeting with soc worker this week for more info (supposedly skilled in memory loss issues) maybe will help. After comparing side effects listed to moms symptoms, I immediately took her off Namenda. She had some of the worst ones. Don't know what to do for her. I'm scared and overwhelmed with stuff that needs to be done, dealing with my own health issues (breast cancer, depression and anxiety, etc), I get very little support from sibs. I am getting a 3-week vacation in Sept, covered by 2 sisters and 1 bro. Oldest sister (retired with no extraordinary responsibilities), informed me that she won't be available for respite till after June, 2015, as she's planning her daughter's wedding. As my primary backup, that leaves me with no hope of another break till then. Mom gets worse and sibs seem to step further back. I'm watching her decline physically & emotionally and it breaks my heart to have so little support. Getting some HHA help soon from ofc for aging, that will be a help, but I'm losing myself and my mom in the struggle. Can't leave mom alone since she's so afraid, so she goes with me everywhere. No privacy, and she's cut off some of her best long time friends. Need support, but don't know where to get it. Any suggestions?