Ok I think maybe your anxiety is getting on top of you. Try to relax, holidays should be something to look forward to,
no you shouldn’t bother to take gift bags and people can only respond to whay you wrote which was to take gift bags to thank them as dealing with your family will be a lot, people are kindly trying to point out on a short haul flight they won’t be dealing with your family, no more than any other family. Be it the single mum travelling with 3 young kids alone, the passengers with additional needs, both physical and mental on. Not as they don’t want to, just as their time is fully accounted for.
i suspect a lot of this is due to this being your first flight, so you don’t know what to expect, but take it from me, I travel a lot for work, flying short haul is fairly similar to catching any other form of public transport.
get assistance if you need it pre and post flight, for hidden disabilities this will be a sunflower lanyard, for physical there will be wheelchairs etc,
youve done what you can, try to calm yourself down, and relax, it’s a holiday, the first time flying will feel nerve wracking, but you will soon realise it’s very simple.
and if you’re struggling at home, then do speak to a gp or social services who can support you,