Tachycardia two days before due date

Starting at 39w4d, I noticed I was unreasonably fatigued, but just chalked it up to being nearly due with a large baby (I’ve been measuring 2 weeks ahead for the past couple months). At 39w5d (yesterday), I slept or had to lay down most of the day and was lightheaded so I googled my symptoms. Most of what I found suggested I’m anemic (fatigue, lightheaded, short of breath). Another symptom is high heart rate. I had my husband check and it was indeed high (120-135bpm) so I’ve been monitoring it with my Apple Watch. It should be 60-90bpm. Baby is moving regularly. I’ve upped my iron, folate, and B complex supplements.

All online anecdotes say people get monitored for tachycardia (high heart rate) but it goes away after the baby is born. Does anyone have any experience with this? I don’t know if it’s even worth bringing up to my doctor since I’m so close to the finish line.