I had a hard transition to motherhood, too, and my first baby was relatively easy.
One thing that really helped me was to realize how short his wake times were. At 5 months old, he was only awake about 60 minutes at a time, including feeding time. He nursed when he woke, and he nursed to sleep, so that was a big part of his awake time every day. I learned to watch the clock, and I'd try to be nursing him, swaddled, at that 60 minute mark, so that he could fall asleep. Luckily, he'd often stay asleep, but even if he only nursed/napped for 5 minutes, he was a much happier baby for it. Before I realized how short his wake times were, he was much fussier.
I swaddled him until he was over a year old, for every nap and every night-time.
He is still (at 3.5) on the very high end for sleep needs, and you can really tell when he doesn't get enough sleep. Of course, ymmv on this, and there are babies that don't need much sleep. But, mine did, and he was unable to fall asleep without help (swaddling and nursing and a quiet place), well, forever it seemed. So, I helped him, and he was much happier for it.
FWIW, he is very intense (even now) while he's awake. VERY. He is one of those 100% on/100% off kids, with no gray area. Makes life interesting.
He cried bloody murder in the car for the first 6 months, too, so it made getting out really incredibly hard, and I limited it a lot.
Other things that worked for me in those early days were a daily shower (it was also important to my sanity), a weekly "play" group, trying to simplify my life (cooking some on weekends so that dh could hold him, really prioritizing which things made me feel like my house was "clean", etc), and sleeping when I could, even if it was 5 minute cat naps with the baby.
Big hugs to you as you make this transition! It IS hard, but you're doing a great job.