I've Had The Nexplanon Apx 18 Months Now. My Son

I've had the Nexplanon apx 18 months now. My son is 19 months old. Irregular bleeding the whole time. Now I've noticed mood swings, extreme tiredness, nausea with vomiting at night, weight gain and breast leaking clear fluid. What are the chances of becoming pregnant with this birth control and what should I do if I get a positive result? I'm scared of effects to baby