Idk what's going on

Elizabeth
So back in November, I started taking birth control, ever since then I don't know what is my period and what's just spotting.  I think I got my period at the beginning of this month, dec 3rd -7th but now I'm bleeding again since like the 19th or 20th. 
Both are very very light though & I have no idea if it's all messed up because I just recently started birth control ... Any suggestions on what's up with me ??