Can spotting sometimes take the place of periods? i'm very irregular. have been spotting for 4 days. very light pink off and on. should i be worried?

Spotting: Some people will have a very light period, more like spotting, especially on some forms of contraception like pills. If your periods are "very irregular" you should have a full evaluation by your physician to r/o any significant problems.

Need evaluation: It is not normal to have irregular periods. There are several causes, some minor other serious, that may lead to abnormal cycles. You should see a physician soon.