My BBT jumped by almost 4 degrees? What does that mean?

Emily

This is my first time tracking bbt and I found out I normally run low temperatures like my mom and sister do (96.3 or 96.5) but this morning my temperature jumped to 99.6! I don’t feel sick at all 😂 but that’s a big spike to me. Is this suppose to indicate something? Let me know in the comments what you think because google isn’t giving me an answer.