HELP. ..4 DPO

Hey ladies. I need help. I believe I'm 4 or 5 dpo and I noticed that I'm bleeding lightly. I've always had regular cycles so this is new to me. I'm taking geritol and prenatal for the last month (together) and for the last couple of days I've been exhausted and achy breast (do not ache all the time). Is this something I should be concerned about? Please help...all comments are appreciated.