Oh Green
Your hubby needs to help out stat! Glad at least you have help from your mum.
Yes, this is what babies do. You're probably at around the worst of it right now - colicy/refluxy/unsettledness/whatever you want to call it tends to peak at around 6 weeks.
A lot of parenting is trial and error - we just figure things out as we go along. Sometimes things work well adn we give ourselves a little pat on the back, and sometimes they don't seem to... and unfortunately at this point we berate ourselves for doing the wrong thing (but how do we know until we try?). You're still building your confidence. Confidence comes from competency and competency comes from doing things (ie, trial and error) so as difficult and overwhelming as this is right now, I think this is a really important process. You will get there
And just putting this out there - your supply may have dropped, but you will still have milk; it's only been a few days.

Agh, burnt my muffins. Sorry must dash again