Sleep regression or dropping nap?

Am

Baby is 7 and a half months, has always slept well, in previous regressions only had a week or so or trouble with naps and bedtime, has slept through the night since about 3 months. This week she has been having a 30/45 min nap in the morning after a 2.5 hour-ish wake window and then having a 3.5 hour wake window and then napping for over 2 hours but she wont nap until shes exhausted. After than its about 3 hours until bed and bed time isn't effected by it thankfully. So I'm unsure if she's going through a regression or just dropping down from 3 naps to 2. She used to have 3 45 minute naps.