Help with answers

Hey ladies,so I'm freaking out I have a toddler he is just 1yr4mnts,and I had my last period on tenth of November. I haven't had a period for this month this is the longest I have stayed without a period,I'm on a pill by the way..but I'm just scared that I might be pregnant I missed about 3pills and had unprotected sex with hun..the only symptoms I'm having is backache and fatigue....I don't know what to think have any of you been through this,what was the outcome?