cycle is changing all the time...

Samantha
Hey everybody, 
I need your opinions on something please! 
I've been having my period always regularly, +/-1 or 2 days but usually quite on time. Now, in November I didn't get my period. It came 3 weeks late. So I had it in December and now I got my January period 10 days late. 
Fist I thought I would be 3 weeks late because my boyfriend was away for three weeks and when he came back, my period came and I thought it could relate to that because my body is very used to having him all the time... but now he's been here all the time so that can't be it and my period still came late... 
Do you have any opinions? Should I go and see a doctor? Or what do you think? All thoughts are very much appreciated!! 
Thank you ladies!!