Brief background: I have a particular small group of friends I have known since school (we are all same age, give or take a couple of months). I am the only one of the group with children, I'm also the only one who is single.
Over the years I have helped out all of them many times. I've had 2 of them living in my house (pre DC), I've helped them move house 2/3 times each, my Ex (who is in the building trade) did quite a few bits and pieces of work for them for free, I have helped them out with legal issues, jobs, CVs, did all the party prep and decorating for one friends DP's birthday (despite it being the day after my relationship had ended and I was utterly heartbroken...but knew she couldnt manage otherwise) and for another of them, spent every weekend for months trying to do up her house so she could sell after she got into financial difficulty. They come to me every Xmas, and when I was with Ex, used to come round for dinner/drinks every month or so.
Ex always said they took the piss, a slightly petty example but one which used to drive him made was if they came to my house they'd help themselves to Coke, but in their home we'd be offered water...but Ex wasn't the nicest person himself and had an agenda in isolating me from my friends so I wasn't that accepting of his opinion.
Anyway fast forward to now, and I've just turned 40. I'd planned a birthday party at my house (last night). I have been v stressed about the whole turning 40 business, together with work pressures, troubles with teenage DC, going through mediation with Ex etc etc. Anyway in all this I asked friends for help with party prep (all live within 30 mins of my house, and have v much 9-5 jobs). 2 weeks ago they came round for an hour, most of which they spent drinking tea and chatting. I asked when they could help next. They were all busy the next weekend. I said OK, can I have your help all day Saturday then? (ie yesterday, the day of the party no more than I would - and have - done for them). No, they were 'busy' but they could help for a bit in the morning - and would tell my DC what to do so they could help me 
. I was a bit terse in my reply, and said that wouldnt help, I had lots to do, I really did need more help than a couple of hours (otherwise I wouldnt ask for help all day). anyway, it ended up they came over Fri night (did nothing) so they could be here early Sat (didnt end up doing anything til mid-morning, spent an hour getting some garden furniture out of the shed and 2 hours putting up a gazebo. I made no comment on the speed or lack of, I was literally running around everywhere doing stuff. I then overhear raised voices indoors (they'd gone in for a teabreak) and it's clearly about me, along the lines of saying I'm an ungrateful bitch. Later, after 2 of them have gone, and I'm chuntering to myself about it as I clean, other friend overhears me and says the issue is I've been utterly unappreciative of them putting themselves out, of how much they've done (I did say, well Ive not exactly sat on my arse doing nothing), how I need to show more gratitude, how kind it is they came over the night before and all Ive done is order them about
Anway, they all turned up to my party, ate and drank plenty, nothing further was said, although I didnt really speak to them much. The issue for me is I don't know what to do now - do I just ignore it and carry on as if nothing happened? It feels like I've let them get away with it if I do. I've done stuff for them for years no reason other than that I like to help, my motivation wasn't their gratitude. Part of me is tempted to let the friendship wither, but as 2 of them have parties in the next 3 months (which they have already asked for my help with) that would be awkward...