Reflexive Verbs/Pronouns vs. "Doing" Verbs

[LaPolicia]

Ok so here's my question. I know what reflexive verbs and pronouns are such as acotarse, bañarse, lavarse, etc. but I have a bit of trouble deciding when someone is doing an action to themselves and when they aren't. I know words that end in "se" like lavarse are usually these reflexive verbs as a rule of thump though.

For example, I was thinking of the sentence "I'm eating." Well technically, the correct answer in my mind is "Estoy comiendo", but it seems like its something you could be doing to yourself if that makes sense. So I thought it could also be "Me Como" as in "I'm eating myself" or "I'm eating." Is there really any good way to differentiate when someone is doing an action to themselves and when they are just doing an action in motion "ando/iendo"? Another answer would be "Ello corriendo" becoming "se corre" even though thats probably not right.

Anyone see where I am coming from on this??? Are there exceptions to the "se" ending pronouns/verbs where you do an action to yourself or are you bound by it when doing something?