I think I know what you were trying to do here. You wanted to make this tool proprietary software -- which you did, by including the copyright disclaimer in the README. What you also did was add the GPL, which is conflicting.
Legally, you're in a gray area because your copyright statement says only you can "profit" and profit is arbitrary (could mean in monetary gain, attribution, etc). To cover all bases, you should remove the GPL (because we can still see the source) as well as adopt this proprietary software note.
I think I know what you were trying to do here. You wanted to make this tool proprietary software -- which you did, by including the copyright disclaimer in the README. What you also did was add the GPL, which is conflicting.
Legally, you're in a gray area because your copyright statement says only you can "profit" and profit is arbitrary (could mean in monetary gain, attribution, etc). To cover all bases, you should remove the GPL (because we can still see the source) as well as adopt this proprietary software note.