Switched from regular thermometer to BBT

Kristie • TTC #1 since June 2018 - Scotland 🏴󠁧󠁢󠁳󠁣󠁴󠁿

Anyone else done this? I broke down and bought a BBT and it arrived Saturday. Started using it Sunday (CD 31) and my temps are very low. No AF yet. According to Glow I’m 4 days late (other app says 5). Cramping since Friday. I don’t see where I ovulated. Temp at 330 every morning since I got new thermometer. Any insight?