Could it be implantation or early period?

Okay, I'm over 35, I have one tube remaining, my cycles haven't been the best the last few months. I had a regular period in December then it was 45 days until my next period in February mid month. My March cycle was about the end of the month. I'm not scheduled for my monthly for another week. Today I had some sharp pains briefly on my left side(only tube I have left), and some dark spotting. The spotting was evident when wiping but then not the next time. I dont feel differently, no sore breast but I did wake up the other day feeling I was going to puke. I do have history of ectopic pregnancy(lost my right tube), and endometriosis. I dont want to get my Hope's up but the only other time this happened I was pregnant. Tia.