You are not alone! I could've written this word for word.
Eating every 2 hours at her age is NOT too much. My LO turned 3 weeks today and is eating every 1.5 to 2.5 hours (except she usually has one 3.5 to 4 hour gap at night if she sleeps well). I've found that she sleeps better (for the most part) if I make sure she's eating roughly every 2 hours during the day. It makes her wake up which saves her longer sleeping for night time.
I think we had a small growth spurt around the 10 day mark, and we are working our way out of another one right now. She has been eating A LOT more the past few days, and honestly I think I can feel her getting bigger day to day!
She prefers to sleep on our chests as well. She sleeps fairly well in a RNP, and today she napped for 1.5 hours in her cradle (which is the best we've done in there so far). I'm told they will work their way out of this little stage... in the mean time, we're doing our best to put her down to sleep during the day, even though it's tempting to hold her adorable little self 24/7.
As far as teaching the difference between day and night, many of the ladies on here have suggested starting a routine before bed. It won't help immediately, but should be useful for bed time in the long run. This includes things like keeping lights on, being noisy, etc during the day... and being quiet, low lights, etc at night. I'm also doing the every 2 hour feeds during the day to help encourage longer sleeps at night (like I said above). Hope some of that helps, hang in there!