Several days late

Alyssa • I`m 17, have an amazing bf, and i go by different nicknames depending on the group. I have a lot of friends and groups.
I'm 17 years old. I.. I don't know what to do.. I'm frightened and worried. I don't know how to bring this up. I had surgery 3 weeks ago. Could it have postponed my period or could I possibly be pregnant. And should I take a test? If I am how do I tell my boyfriend? I don't think I'm ready for this..