Look, sometimes as women we martyr ourselves. We do the majority (if not all, as a lone parent) of the housework, childcare, appointment making, present buying etc, then expect other people around us to appreciate it. They won't. So sometimes YOU have to put YOURSELF first. Most of the time other people won't realise what you want - you have to vocalise it.
Grockle, with the Mother's Day thing, why did you invite family round when surely you'd realise that you'd end up doing all the hard work? Next year, TELL people (ie your DP) a few weeks in advance that you want to be taken out for Sunday lunch with the kids, so that you don't have any cooking or washing up to do. Tell him he'll need to book a few weeks beforehand because it will be busy, then leave it to him to sort out. After the meal, go somewhere nice afterwards, say cinema or just for a walk - whatever YOU fancy.
When you say your DP sometimes irons and hoovers, do you mean at your house or his? It's not very clear from your post because you say you don't live together, but I really, really hope you're not doing his housework at his house as well as your own. If you are, stop now. It's not your responsibility.
Pickyourbrain You're mothering your ex. He needs to take responsibility himself. By all means email him the school holidays if he doesn't get them direct from your DD's school, and her weekend events, but leave it at that. If he forgets to arrange childcare, tough - it's his problem, not yours. If he forgets the events, tough - it's his problem not yours, and when your DD starts to become annoyed with him because he forgot to take her to a party or whatever, he'll soon start to remember. He only 'forgets' because you enable him to, as he knows you'll remind him.
I'm assuming that as your DSD has periods she's old enough to buy tampons herself, is she not? If not, she's at least capable of adding what she needs to the shopping list.
Present-wise, why not give your DD a few pounds and let her pick something for her dad herself from the supermarket or pound shop? She could also draw him a card, to save your money. You don't say her age but I'm sure she'd enjoy doing that, and the onus is less on you to get presents/cards for your ex. With regard to presents from DD for you, doesn't your DP (or your parents) get something for her to give you? If not, maybe you should bring it up with one of them to take on that responsibility until your DD is old enough to go shopping alone.
I'm not trying to be harsh here so apologies if I sound it, but I hate seeing women being put upon with nothing in return. But the fact is if you let these things happen, they will, so insist on change and change will happen.