An addiction on to cellphones

I kept my cellphone around me all the time, and checked for missed calls and texts in every 10 minutes (This is not incorrect, but it is more natural to say: I keep my cellphone around me at all times, and check for missed call and texts every 10 minutes) .

Today, I left it at home and felt uneasy all day till until I came home from work. (till is very informal, and is not generally used in written language. It is sometimes used if the writer is writing is a specific dialect, such as a rural, southern American dialect ).

Maybe I have became become too depend on it.

From now on, I will set the a time limit on cellphone usage.

It it is because recently I lost track of time and ruined impotant important matters I should have done it. (This sentence is  confusing, but I understand the meaning)

You could say:  Because I recently lost track of time, I neglected ( you could also say forgot about) important matters I shouldn't have. This sentence would also be better placed before: From now on, I will set a time limit on cellphone usage.

please snap out of it. (Again, this sentence is a little confusing because it is a command, and would only make sense if this was for someone else.) You could say: I really need to snap out of it. Make sure to include yourself as the subject. 

An addiction to cellphone X  > Addicted to my cellphone.