10-mos old baby

Hi. I'm a mom of a 10-mos old baby who used to be well-behave. However, one day, she showed a very unusual behaviour that I never thought she'd adapt at a very early age or I don't know if it's just me who thinks like it. She would throw a tantrum whenever she doesn't get what she wants.Dati naman kapag nag "no" ako,wala lang sa kanya.Ngayon,iiyak sya at kakawag kapag di pinagbigyan..Halos ayaw nya na din sumama sa akin unless dede time nya. Feeling ko tuloy napabayaan ko sya. I'm a working mom and I leave her to a nanny during weekdays but I see to it that I spend time with her at wkends. Pa'nu ko po ba ihahandle at ididiscipline ang baby ko?first time mom here.