When a rabbit is very close to her due date, sometimes you can see the babies kick when she's laying on her side. You can also just gently put your hand against her side and wait to see if you feel kicks (I wouldn't squeeze - at this stage it isn't necessary and it'll annoy the rabbit).
The thing about kicks is that until you've seen/felt them, you can mistake the movement of the rabbit's gut for the movements of kits. The big difference, to my eye and hand, is that gut movements are a rolling, rhythmic type of action, while kicks are abrupt and much more distinct/forceful. So, if you're new to this, what you felt three days ago
might have been gut movements.
The caveat is that first-time does can be very cryptic in their pregnancies (kind of like with my first pregnancy, no one knew I was pregnant - not so much in later pregnancies!
). I've been fooled a number of times by tightly toned first-time does. So my suggestion would be to wait 40 days after the last day she was in with the buck, then call it a miss and try to rebreed her.
Palpating for embryos is generally done between 10-14 days. I've not had much luck with it, but I'll admit I haven't tried very hard to learn how to do it. My rabbits tend to be reliably pregnant when they're bred, so I haven't taken the time.
By the way, I agree with
@Her Farmstead Rabbitry about the 5-day breeding practice. It's not really necessary and it does make predicting a kindling date much harder. Everyone has different approaches, but an old ARBA judge told me about a study (which, frustratingly, we haven't been able to find in print) in which the highest conception rates and litter sizes resulted from breeding the rabbits initially, waiting an hour, and rebreeding them. No other time interval was as effective. I have found this approach to be very reliable (and like I've mentioned elsewhere, my does usually have 10-16 kits per litter in their first year!).
Honestly, though, a single fall-off by a fertile buck with a healthy, willing doe will do the trick!