BBT beginner?

My boyfriend & I have been trying to get pregnant & I have PCOS so it has made it difficult. I’ve only been charting my BBT for 2 days now & I recently just finished ovulating when I started taking my temp & the first one it was 98.6 yesterday & today it’s 97.7, i’m new to all this so I’m not sure what in 2 days that difference could mean so any tips would be appreciated!! I also should add that I started taking Pcos/fertility supplements once everyday so I believe that is what really helped me ovulate for the first time in a very long time. We also BD’d the 25th & 28th.