Hello Tony,
Yes it's all normal, if you can read Oliver James book called Contented Dementia, it will help you to cope with your daily situation, it gives practial help in dealing with daily life, if you can imagine our memories as a photographic album, without dementia we call recall (look back) into the album and find anything picture (memory) we like, but for a person with DM they have blocks of pictures containing facts missing, hence their need to search for answers when questioned, this is what then we see as their distress, but also if the memory can't be recalled for a fact, that will include a negative feeling and cause distress, however, if we go to the place where the person with DM is at that moment in time, don't question or contradict, accept, then the person with DM will have a happy memory and with it created a happy feeling. The more pictures missing, the less facts to be recalled, but then they are left with just the feelings, so if we can create a ribbonning effect of more good feelings the person with DM will be more positively contented. Best of luck. Ps the book is brilliant.