It does get better, but (for us at least) very slowly. And be prepared for your HN infant to be a HN toddler/child too - though at least they usually stop the screaming *all* the time thing...
DD1 was like that - I think she just hated being a baby. She was utterly distraught for the first year or so of her life - was never happy, couldn't sleep, feeding difficulties, screamed and cried what felt like all the time. But gradually, as she gained in independence, she became slightly better. She was *driven* - reaching all physical milestones very early - crawling at 4 months, walking at 9 and then running a couple of weeks later, walking up and down stairs before 1 etc. Signing also helped immensely since because she was so focused on the physical stuff she was a later than average talker, but at 15 months I remember counting over 150 signs that she knew, so at least she had a reliable way to communicate with us. And when she did start talking she took off overnight and hasn't stopped since!
Advice from the trenches:
- Let the housework go as much as you can
- Get as much sleep as you possibly can - however that needs to happen
- Don't feel bad about putting the baby down to do essentials
- Try not to hold yourself to the same standards as other mums (this might be a bit easier for you since you already have one kid, so know what it's like to parent a "normal" baby - what you're dealing with is completely different from the normal baby experience, as you know)
I wasn't very good at doing any of the above, so I ended up pretty traumatised from DD1's early years, but these are the things I would tell myself if I could go back - oh and ASK FOR HELP!!! Don't feel guilty that you need help - a regular baby is hard enough work, but a HN baby is enough to exhaust 4 adults at one time! (Ask me how I know!!)
I've also heard that colicky/HN babies often turn out to be brighter than average and I think that's probably true for DD1 - so that's something to hang on to as a consolation I guess... They are certainly very *intense* people, and that can be a good thing as they get older - They love you intensely, they get passionate about their interests - makes them very rewarding and interesting to be around.
:hug and GL