My mom tried claiming me as a dependent on her tax return and I meet all the criteria except that I made over 20k and I paid for my living expenses. Because I lived with her for 7 months this year, it tells her that “Even though R**** lived with you for more than six months in 2017, he supported himself, which means he can't be your dependent. But the good news is he could help you get other tax savings.” And she ended up getting money for me living with her and it lists me as “EIC or Dependent Care Credit Only”.
Now does this mean I can claim myself on my tax return because she wasn’t able to claim me as a dependent?
Yes, you can claim yourself on your return.
If your mother did not claim you as a Dependent, you can answer the question that no one else is claiming you on their tax return.
The following IRS interactive site may help clarify your question further.