Lexi and Tucker tied up on labor day weekend... She only has one week left. her belly is huge

I feel so bad for her I did get a sonogram done and the vet said she looked good and seen 4 little ones I am so excited but nervous too this is the first time I have ever had a letter from a dog so small I hope she is okay . If any one has any advise I would appreiciate it thanks Lexi s Mom