This is plagiarism. Plagiarism is a form of lying and a form of theft. It is a problem. It's a big problem that worsens every day.
What if someone with whom you worked took everything you completed then presented it as her/his own?
Someone took the time to write something, it is hers or his. Respect the time and effort that person took to complete a task that might be a part of his or her job.
According to this thread, as it appears, you wrote what you copied and pasted. You didn't; you plagiarized.
Next time, quote it.