Advices please?

So I'm 18 and last month my period was right on time and it was unusual, it lasted for like 10/14days medium to light flow through out. This month I'm now 2weeks late according to glow . I did she'd like 2/3 drops of blood weeks ago but that's all. I haven't had any symptoms other than my usual pms (cramps, leg ache and massive cold) . I don't know what this could be?