Need help with my pregnant guinea pig plz?

Ok the thing is my guinea pig is pregnant tho i dont have a clue how far along she is...We have had her for 5 weeks we bought her from the pet shop pregnant! When we bought her she was noticeablt tubby, now she is a beast so so fat sticking out at both ends of her belly and ber belly literally trails on the floor, also her back end is noticably flat!! Can anyone tell me maybe how long she has left? Trying to add it up myself id say anyday now but id like someones elses oppinion...thank you xx