Random Bleed 7 days before Ovulation

I've been sic the last week with random allergies/head cold. I've had a migraine the last two days and neck tension. I'm so confused because today I went to the bathroom after lunch and wiped a large amount of blood. I'm 25 days from my next cycle (35 day cycle avg) so I have no clue what this could be. Anyone ever have this happen? Why am I bleeding?