There is no harm in eliminating gluten, I'd say go for it! A lot of people are gluten intolerant without being actually celiac. The fact that you got a headache eating bread is your body is trying to tell you something!!!
(Personally when I gave up gluten for 3 months then ate a wholemeal muffin I ended up crashing out on the couch for 4 hours and woke up sneezing with allergies!)

This might seem obvious... but you should focus on protein! If you're tolerating fish, poultry, beef, eggs etc then its a good idea to make these a large portion of your diet going forward. and tasty too!

A detox like you've done is a great way for people to eat clean and slowly re-introduce foods to their diet, and then observe if any items irritate them. Now you've learnt to listen to you're body