is this a good sign?!?!

My LMP was 10/2/16, which as of now makes AF about a week late. I wish that alone was enough for me to get my hopes up, but my period is as irregular as can be (however, since July it's been pretty on schedule). Anywho, I have been experiencing some mild cramping that feels very similar to period cramps and very light brownish bleeding, but not like a period flow, VERY light. Could this be implantation bleeding? I experienced similar bleeding when I was first pregnant with my DS 6 years ago, however, I don't remember the cramping as much. Also I've been extremely tired lately, which was also a pregnancy symptom I've had before. Should I take a test or am I imagining things?! I want to be pregnant so bad, but I would be so devestated if I wasn't :/