It all depends.

Are you ONLY upvoting your own stuff and NOT upvoting anyone else's useful contribution on any of your posts?

If the answer is yes then I think that IS a problem. You need to understand your responsibility as a whale to others who are struggling to get a foot hold. In the long run, helping others to feel they have a place here on STEEMIT will only benefit your investment by increasing user participation, interest and ulimately the STEEM price.

If however you're upvoting yourself AND helping others on their way too, then more (STEEM)power to you.