To test or not to test?

Hey! it's 3 days before my period is expected but my breast are hurting so bad that I know something must be going on.. at first I thought might have mastitis ( I have a nursling still) but it's been a week so it's not. I just don't want to test to early but I also do want to.. I hate wasting test tho :( opinions please? Since I'm feeling early signs would my test be accurate??