If she was in with a buck for a week and she is over 6 weeks old (which she should be anyway if you bred her on purpose) then it is most likely that she is indeed pregnant. She would start to show obviously after 2 weeks from conception and there will soon be no doubt. If there are no signs of pregnancy you still need to wait at least 3 weeks after the time you removed the buck, just in case she's pregnant but not showing (which can happen).
It can be really difficult to tell, sometimes I've had does who have given birth to smaller litters and they havent even looked a bit chubbier than normal when pregnant. I'd say the first picture looks like a rounded belly and the nipples are showinng a bit so those are sort of signs she is expecting, maybe another week or so.