7 week old very fussy in the evenings

7 week old is very fussy in the evenings. This can last from 6pm-midnight, and it is very difficult to get her to bed. She’ll nap at 7-8ish within that time, we then do bath and feed and she just will not sleep untill midnight.

This has been going on since 3 weeks and does not seem to be getting better. She becomes very fussy, crying out with these short shouts (not continuous tearful crying), kicking her legs a lot, very agitated. Being on the breast soothes her but she’s still very fussy, pulling her self off and relatching continuously and lots of kicking. She doesn’t seem to have gas, nappy checked etc. My partner has given her a bottle of expressed milk and she barely touches it so it’s not hunger. We are at a loss as to what to do and what is wrong, and I’m exhausted going to bed so late and soothing her for hours.

We recently took a long car trip (3 hours each way) over the weekend to meet friends and family. In the evening of this trip on both nights she slept from 9:30 and did not fuss like usual. (on the first night she napped 6:30-8:30, woke fed and was in bed at 9:30).

We usually are at home in the afternoon onwards, going out in the mornings for a walk, coffee dates etc. I’m wondering if this is having an impact on her behaviour? On our weekend away we were out and about in the afternoons/evenings? Could she be napping too much in the afternoon?