Ragarding pregnancy confusion. What not.

I was with my boyfriend on new year eve. I thought i was in safe period time..so dint cared about any precautions and any pills after that...but then my three periods held almost regularly...first one in January end little bit delayed... Second was normal and third one in march was bit early....only diff was ..these were not that much bad as it use to b every time....i mean they were light....but now fourth one...is being already delayed by 15 days...i was expecting around 25-28..but no signs till now.... I'm in extreme pressure...what to do and what not...moreover nowdays i live at home...unlike earlier in pg...nd can't arrange orega newd anyhow ...plz suggest wht Could b the possibilities and steps that i should take now....i am worried and depressed.