Bedtime help... I’m exhausted

My daughter was born June 1st, due May 27th, so she’s 7 weeks old. For the past 2-3 weeks bedtime has been a serious struggle. She does fine during the day. I get her up around 9:30 and feed her every two hours starting at 10:00. She eats, I hold her up for 20 minutes because of her reflux, then she goes down for a nap. She sleeps about an hour total each time, including the 20 minutes I hold her up after she eats. Then when she wakes up we play for about 30 minutes before she is ready to eat again. She fusses a bit at feeding sometimes but usually nothing unmanageable. Our problem comes at bedtime. She is not fussy at bedtime usually, no more than day time feedings so I don’t think it’s colic. I feed her at 8pm and she won’t go down for the night until at least midnight, but sometimes as late as 3am. Y’all I’m struggling. I can’t be awake that long. I end up crying most nights because I’m so exhausted. She will eat and fall asleep while I hold her upright but then as soon as I put her in her bed she will start wiggling around and wake herself up again. Sometimes I get a 30 minute nap before then but not often. All she wants to do is eat and be held while she sleeps. I don’t think we have a bad routine during the day or that her wake and sleep times are off based on stuff I’ve been researching so I just don’t know what else to do. I’m feeling very tired and discouraged.