Re: New to this.
Sounds like acid reflux.. but just to throw another suggestion out there...
I shared some of your symptoms growing up and I always just thought I was "having a bad day" or it was period related or just a "blah day" turns out that I had a food allergy.. Celiac Disease.
I was always nauseated after eating, felt like I had rocks in my stomach, was bloated, and gassy (how embarrassing!) constant headaches, tired ALL the time, withdrawn, pale, problems in the bathroom, aching/cramping/pain in my abdomen and lower back and sometimes my ribs would feel like they were bruised.
If this sounds anything like you then do a quick search on Celiac disease/Gluten Intolerance and do some reading. You can also try cutting gluten out of your diet for a couple days/weeks and see if anything improves.
Good luck.. hope you feel better.