After shots its normal for them to be sleepy, but by 1 month my son started sleeping longer stretches at night. If baby sleeps that long, its fine she will wake when hungry.

It's normal for my 7 week old to sleep 7 hours straight. She's slowly been working up to it. My son was a good sleeper at that age as well. Also, my son has always been really sleepy after shots so I wouldn't be concerned yet. But if you are concerned, definitely talk to the doctor.