Bbt fluctuations

Jessica • Edd 11/9 #3 after losing 6 mo old daughter last July & having a tubal reversal in September. Hoping for a rainbow baby!
So I have been TTC for a year.  From sep- April my bbt was always 96.7ish before O and 98.0+ after.  I always ovulated day 15-16 and started AF day 27-28.  I stopped taking bbt after a chemical in April and took a "break" I started up again this month and so far it's been way different. Like 96.5-97.1 before O but so far after like 97.4-97.9.  Not near the contrast or spike I've had in the past.  Anybody else experience something like this or have any insight?