sunnyweather :( Sleep deprivation is just horrible, isn't it :(
Sometimes just getting a good few hours of sleep can make all the difference. Certainly what you're going through is TOTALLY normal. As is a whole other range of things including babies sleeping 12 hours at this point (although that's rare!) and babies who wake even more often than yours. 6 months can be a really tough point but it will get better soon.
It's very common to feel "touched out" or like you're the one with all the responsibility. Again, getting a break when you feel like this is important, yet so hard.
Are you doing puree or baby-led and what sort of foods have you started with?
Can you bear to have him in bed with you and ditch the cot for another month before trying again? That way you'll not lose that sleep trying to re-settle him.
Can you try going to bed really (stupidly - 7 or 8) early for a few nights to catch up a bit?
If you are not able to express you can certainly try formula (infant, not follow on) to give you a break. Do you need information on formula?
One thing though - he is clearly telling you that he needs that night milk so cutting it down is a battle you won't win! So there are workarounds (eg co-sleeping and a few early nights) or substitutes (eg formula) to help you through, which will probably mean you feel up to going back to EBF after a few days.