I have a severe buring sensation in my eyes, waking me up every night. getting worse... help!?

I'm a 40 female with a 17mo baby... this started 4 years ago with a scratched cornea... intermittent waking with burning, but now it's BOTH eyes, severe burning/gravelly feeling in eyes waking me several times every night. I've been using saline and similisan dry eye or allergy eye relief along with homeopathic histamine...nothing seems to be helping and it's getting worse. Not so much a problem during the day, just when I'm sleeping. I'm guessing it's allergies OR dry eye, but I'm not sure anymore. Any help would be greatly appreciated. I have no insurance so I can't just go from dr. to dr. until this is resolved. I would prefer not to use prescription drugs, anyway, if possible. I would like to find the cause for this and let my body heal itself.