ginsberg16

I planned to apply to graduate programs in chemical engineering using a LOR from the professor who I have been working in his lab and two LOR's from the post-docs who I have been working closely in the labs. My friend said that I would need at least 2 or 3 LoR's from faculties. I didn't keep good relationships with other professors or lecturers. And It is too late for me to do that because I am about to graduate. Additionally, due to my average gpa, I would have more chance to get accepted with letters from post-docs because they know me well. What should I do now? Is it true that you need most of your LOR's must be from faculties? (I checked graduate programs's website; some of them don't say it clearly at all :| ) Did anyone here actually use 2 or 3 LOR's for your grad school application without any problem? Thank you very much! I appreciate all replies