colic? reflux? normal 1st month behaviors? help! tired mama

A
Hey mamas! So my baby will be 3 weeks old Wednesday and recently has been having crying spells that can last for 2-3 hours (maybe some breaks of quiet within). I feel like she's inconsolable. I feed, pacify, change her, take clothes off, swaddle arms in, arms out, put her on my chest, bounce, walk, make white noise and sometimes it doesn't help. It's definitely worse in the evenings which my husband hates because that's the only time he sees her. She is exclusively breast fed and a pretty good eater. I make sure she empties a breast to make sure she's getting fore and hind milk. Sometimes I have a hard time burping her and she has been spitting up a little more (2-3x a day). She also has a rash but only on her little booty hole which makes me wonder if something I'm eating is causing some sort of reflux? I do plan to call the pediatrician today  (after a much needed nap because she's finally asleep lol)
Anyone going through the same thing with their LO?