BBT chart

Gemma • 38 years old with a 44 year old SO. Baby boy #1 born December 2016. Baby girl #2 born July 2018. Started journey for baby #3 November 2023!
Hi lovely ladies. So, I'm new to this TTC! I had the copper IUD fitted for 10 months and then my partner and I decided to try for #1 so just before having my IUD removed I joined Glow to begin tracking my BBT. I've been tracking my AF since I had the IUD fitted (in a different app) and my cycle has been between 23-26 days. My CM has always made changes around what I've guessed is my OD so I'm assuming it was my OD on Dec 24th as very wet CM. I had my IUD removed on the 29th Dec. Now, looking at my BBT chart - my temp spiked on 25th Dec (post OD) then on the 29th it had a large drop and now it's higher than before. I take my temp at 5am so the drop on 29th Dec was 4 hours before the IUD was removed. I have had no bleeding or spotting since removal. I don't want to read too much into things and AF is due 6th/7th Jan. What are your thoughts on my situation and my chart? Is there a possibility I'm pregnant? Or is this all usual? Thanks x