Yes - it does get better. I had 4 under 7's at one point and thought I was going mad sometimes - it was very tiring. We were also home educating (long story) at the time and so it was very full on with lots of extra activities to ferry various kids too and hang around amusing little ones at.
Those 4 are all now almost in their teens and are just lovely. They all get on really well together and we have great fun laughing together, shopping and shouting at stupid things on the TV. The dinner table is also very lively. Life is a lot easier - my kids think I'm so laid back compared to their friends mums- Thankfully they don't seem to remember how stressy I used to be. I think you get so tired that adrenalin goes into overload and you feel a little hyper.
My advice would be to find any way you can to take the pressure off a bit. If you have any spare cash get a cleaner (we did for a while).Also the old saying "don't sweat the small stuff" is good advice. One of my kids was really fussy about clothes - fabrics hurting etc. She always wanted to wear pyjamas - I used to force her to put on smart clothes for visiting granny, going out etc but in the end bought some track suits and just let her wear them all the time- granny complained and everyone thought she was a boy but it meant I could get out the door without war starting.This child is now the most girliest smart dresser ever!
I also in the end cut back on some paid for activities, the little ones hated travelling around so much and the naughtiest would lie down and grab the bannisters and refuse to leave the house- it wasn't fair on them to be dragged all over London in the car.I got a piano teacher to come to my house to teach the 3 eldest- so that cut out a trip.
Also have your shopping delivered - order as much as possible from ever reliable Ocado online. My children hated the supermarket and any kind of shop, one would always run off - it was hell! Go out to the park or a wood instead. I also bought toys, clothes etc online.I also stopped ironing - a smooth and a fold worked just as well.
They are small for only a relatively short time. I wish I had calmed down a bit and not worried so much about what other people might think of me and my children and not tried so hard to have them all well dressed, well behaved, attending all the right classses etc.and having a clean house.
Good luck