The problem with sex toys and too much masturbation is that it is "self" or artificial sex and actual sex is part of a relationship with another person. But you get in the habit of a "certain" way and end up not able to have orgasms with another person, not being able to have "good" sex because of having picked up a habit beforehand that circumvents it.

If you are stressed and using masturbation to let off the stress, I would rethink how you can get non-sexual help from contact with other people or other activities that won't link sex and stress relief together that closely so you don't have trouble later. Take an exercise or yoga class or something if you are feeling stressed or talk to a good friend. Being off by yourself masturbating isn't a good place to have to get away from (been there, done that :-)