I have 14 mobth gap between dd1 and 2, they are now 4.6 and 3.2.
like you say the first year was hard, the way i coped was to embrace the chaos! our house was a mess, the tv was on a lot, dd2 had no routine, she slotted into whatever caused least screaming. We were out all the time (i hope you have a good double, i will probably cry when i have to get rid of our phil and teds!} Toddler groups, friends and cafes saved my sanity. Dd2 never slept in her cot, she would sleep in the buggy during the day and in our bed at night, she was always cuddled to sleep.
Please let go of the guilt, dh would say to me, 'this will pass', on days where I just felt overwhelmed by it all,dh would come home and i'd go and lie on the bed and have a good cry or go for a walk with my mp3 player.
It is all so worth it, the girls are now so happy, they adore each other and spend half the time fighting and half the time cuddling. They entertain each other pretty much all day, and have learnt to share and be very caring of others.
It was tough, but you will get there. We now have ds, who is 13 weeks, the girls adore him, the chaos is back, scooby doo is on all the blooming time, but everyone is happy and fed and even dressed half the time!