The prof was well-known for being blunt and sometimes even mean. He was a bit too harsh, because my GPA did not deserved to be called "the bottom of the totem pole." I just went to meet him in hopes of getting honest advice.

By "junior" I guess it's the third year of university? Then it's not too late. I think your profs are telling the truth when they say you're not doomed. The employers who look at your GPA will mostly focus on your 3rd and 4th year transcripts. Those years have the important upper level courses with specific topics. The employers will not likely look at your first and second year courses even though they have poor GPA. So you can still work on your grades and save the situation.