DD slept lots after hers - the evening she had them she slept 6 hours straight which she'd never done before. When awake she was really crabby, and I gave her calpol after that evening sleep as she woke screaming inconsolably - it helped (though was a nightmare to get into her - you need a syringe to squirt it into the side of the cheek very slowly and carefully). She was a bit subdued the next day but then back to normal the day after that.
My dd has had her jabs first thing in the morn - I had always given calpol regardless an hr or so after - I just think a temp is dangerous in a little one and one calpol dose isnt going to do any harm at all - she was fine after first two lots - was worse after 4mth jabs this week, but she had a cold as well and needed 3 calpol doses. A worrying day! Also always been very sleepy and crabby afterwards. The syringe method used to shock her and we worried re her choking but it's easier now to make her laugh and smile and this is when I get the spoon in with her sat upright but slightly tipped back. Takes a few respoons as of course a bit of it get spat back out. Hope your DC still sound asleep x