Your mum is not unique in her wish to 'go home'. There are many dementia sufferers in my husband's care home who hover around the entrance and tell anyone within earshot that they want to go home. My husband also begs me to take him home. It is quite heartbreaking!
The problem is, the idea of 'home' which they have is the home where they live an independant life, where they can look after themselves, where they have the freedom to do all of the things they once were able to do - in other words a state of being in which they once lived and can no longer live. This illness has robbed them of this ability, just as surely as it has robbed us carers of the ability to care for them 24/7 because their needs are greater than our power to do this.
I have been so pulled emotionally that I do bring my husband home for long periods each weekend. It becomes clear to me that he has no feeling of being 'home'. Within a few hours he is restless and just as unhappy as he is in the care home. Being 'home' does not solve the unhappiness, the lost feeling, the isolation and the terrors he feels. I wish with all my heart it did.
So my love, please don't feel that by visiting your mum you are bringing on these feelings. She has them whether you are there or not. The staff at the home my husband is in try very hard to give reassurance and compassion, and this usually assuages their terrors for a while. Hopefully in the time you visit, you can give also her the warmth, reassurance, and quality time together which makes your visits well worthwhile.
xxTinaT