mid cycle bleeding

Chelsea
I have never had any mid cycle bleeding... until now. 
Today was day 4... I guess I should call it spotting. It wasn't heavy enough to warrant a tampon just a liner. 
I also have not gotten a positive ovulation test this month and I'm on cycle day 24 in my typical 30-34 day cycles. I've tested for lh for the last 2 weeks sometimes multiple times a day. 
Of course my husband thinks I'm pregnant because he reads about implantation bleeding. I on the other hand don't think I am and honestly won't let myself think I am because I don't want to be let down anymore than usual.
So have you had mid cycle bleeding? What caused it? Did it continue in future cycles? Any input is appreciated!