Sentence:  She 'd say she did n't feel good on <WSD>Sunday</WSD> , could n't go to church - there 'd be a little argument , but she could be stubborn - and when the old woman had gone , quick pack the things she 'd need to take , all but the dress she 'd wear Monday , and take the bag down to that place in the station where you could put things in a locker overnight , for a dime . 
Meaning of the word marked with <WSD> tags:  first day of the week; observed as a day of rest and worship by most Christians