Possible Pregnancy ????

So my friend thinks she might or might not pregnant. She had sex the beginning of April like around the 4th and (no it wasn't voluntary so don't judge) . Her period came on the following week but she hasn't had a period at all this month yet. Do u think it's just stress or its changing ?? Or could she be pregnant ? I don't wanna give her the wrong advice but she's really freaking out !!! She's been having cramping but other than that no other symptoms ...