Feeling like failure mom

Si

My baby is 7 weeks old and is a terrible sleeper... she sleeps 3 hour stretches at night and then is up for an hour... I feel like I’ve tried it all. We have a very established night routine we’ve been following since 2 weeks and we sometimes have fantastic nights! She has had a night where she slept nearly 7 hours, woke up to eat and then immediately went back to sleep for 4 more hours. But then bam the next night, 3 hours and won’t go back to sleep immediately.... I have many many women around me who just had kids who claim their babies are sleeping through the night and I don’t understand what I’m doing wrong... I’ve tried making baby stay up during the day but if I don’t let her do her own sleep cycle she gets extremely extremely cranky and then overly tired and has an even harder time sleeping so keeping her up doesn’t seem to work. It’s just like the luck of the draw with her... I go back to work in 13 days and I’m going to be miserable if I can’t figure out how to get more sleep.... Any advice or anyone in the same position? I just feel so alone because everyone just talk about how great a sleeper their baby is...