I live a long way from my son, his wife and my new granddaughter. I have been on a learning curve these last few years. Here is my take! Often the problem is with the spouse, if she is female, and sometimes if she is your daughter. It can be a 'territory/we are grown up' thing. So, what to do?
First, if you seem needy as I did when first living alone, they will feel lumbered before you even arrive. The only thing to do is to have genuine social interaction in your life not involving them. A study group, a hobby group, an online activity are all good. Then, you have a social diary, of sorts, of your own.
Next, look up a nice hotel near them and tell them. If they prefer that use it as a bedroom effectively. But treat yourself! It is too late for the Christening but you could have been fine. Next, realise what most Mum's realise at some point, they are shuffled sideways in the pecking order of the new family. See this as a release from usual intensity of responsibility.
Next tip, if you think you are being helpful, check! They may see it as interfering! Next, do not simmer and stew, getting upset. Step back. Think of this as an opportunity to have a nice time.
A happy, relaxed grandmother is a welcome guest. You may never get to stay in the hotel, depending on house space. Either way, CHILL! as they say. Yes, they take advantage, yes they can be insensitive and worse. Rise above it and you will ALL get along better and you will enjoy being a gran XX