Curriculum: you don't have to follow national curriculum. Some people follow set syllabuses (there are about a billion of them you can buy online, lots of them are Christian ones I think but there are secular ones too). Some people follow the National Curriculum, but for many people, home educating is a great way of NOT having to follow it!
Some people like to ask their LEA for advice, and they will certainly give you all sorts of advice, and some of their staff are supportive, but be warned that not all of the staff are really clued up about home education, and sometimes what they really want to see is something which looks like school at home, which it absolutely does not have to be. The websites linked upthread will give you good advice about keeping the LEA at arm's length if that's what you want, and get yourself onto the Education Otherwise mailing list too (it's a yahoo group), because there are many many wise people there who will give you advice and support.
Many home educators are much less curriculum/timetable focused, and do things looking more or less like the Unschooling which is at the joyfully rejoycing site, linked upthread.
It sounds to me, from my vast (hahahahahahahaha) knowledge and understanding of your situation, that your son might well need someone to just be with him, and support him, and help him to regain his confidence for a good few months before even thinking about the academic stuff. And then you'll turn round, and realise that he was learning like a sponge all the time the pressure was off.
Low concentration, lack of response to teacher's instructions can be the result of a child not being ready for the formal situation of school, or of them just not being temperamentally suited to school, not that there is something wrong with your child. Have faith, take him out, and watch your bright, bubbly, inquisitive child return.