Spotting .

Ok so I started my birth control two weeks ago and have been spotting for a few days now , also having mild cramping in my uterus . Has anyone else dealt with this and is it normal ? I've been on BC before but it was a regular (period every month) pill . This new pill is called levonogestril . It's a period every three months . I'm not having any other symptoms besides acne. Any thoughts ?