BBT steadily rising before AF?

Hey everyone, this is my first month charting my bbt. AF is due this Friday, Jan 17th, and I used an OPK and had an LH surge on Kan 2nd and hubby and I had sex basically everyday from the end of my last period until three days after my LH surge. We also have pre seed a shot everyday within the week of ovulation. We've been trying almost a year and we are using everything we can at this point. Anyways, my bbt is usually around 97.10 with fluctuation up or Down of maybe a few .3 of a degree... The past few days I've been at 98.4 and rising as today I'm at 98.61! I've had a few other symptoms but sometimes I get those before AF. Does your bbt usually rise that much before AF is due? Or could that be an early sign I'll get a BFP next week? I'm going to wait to test until Jan 20ty to make sure it's not too early.