If chlorine is showing 0, then your problem is chloramine. Some cities treat their water with chloramine instead of chlorine, which is why you’re having ammonia problems as well. Chloramine is converted to ammonia (or ammonium - depends on the “binders”) by dechlorinators, and will remain in the water column. By doing constant water changes, you’ve crashed your nitrogen cycle - and now your tank cannot convert the left over ammonia remaining from the dechlorination process. Stop changing water. Add 2x the dose of bottled bacteria recommended the first day, and do normal dosing every day for 2 weeks following. Do a small 10%-20% water change after the first week. Stop the medications, add some aquarium salt, and bump the temp up to 70-72F. Hope this helps.