What Causes Delayed Periods, Clear And Stringy Vaginal Discharge And Spotting?

My menstral cycle has always been off by being one or two days late my entire life. I ve had a copper IUD for 6 months now. Prior to that (with a year break in between) I had Mirena for 5 years. My history: I have one miscarriage, three children, and one abortion. In that order. I hate having to worry about extremely late periods. Which I ve had twice, being up to 4-6 days late with paraguard already. So this month I calculated my cycle to be 4 days later than last month. But I still haven t had my cycle. I m 2 days past my 4 day leeway. I figured it was nothing until tonight I had a very noticeable amount of clear, odorless, stringy discharge (for me it was a large amount). Which is odd because I ve never had and/or noticed the notorious ovulation discharge before. Four days ago I had a single light spotting. 6 days prior to that I also had single light spotting as well. I have been sexually active throughout all this time. Is this normal? Am I just being paranoid? And if so, what can I do to ease my mind when these occasions arise? What is the actual likelyhood of a pregnancy with paraguard? Should I use a second form of birth control?