Separation anxiety

So we always see stories about babies having separation anxiety, but what about us Mums? My baby is 12 weeks old, and I just can't bear the thought of being away from her. My Dad and my Granny are always saying, "we can have her for a night if you want some time." My Dad even says he'll even have her through the daytime if I want to go do some shopping or anything. I also have the best sisters, who are both 19 and 22, and they always offer to take the baby for a "sleepover," they say. They are such good aunties to my baby, and I know they would have her anytime I need someone. I am so appreciative of all the family I have around me, and I would never take it for granted because I know there's people who don't have family support like I do. But I just can't bring myself to be away from my baby. The other day, my sisters were round at my house, and my sister offered to drive me to the shop, but because my baby was asleep, I left her at home with my other sister. It felt so strange, as in the full 12 weeks she's been here, it was the longest I've been away from her, and it was literally 25 minutes. My partner is the complete opposite. Like he works full time, I know, and I genuinely don't know how, like I don't know how I'm going to even cope when I have to go back to work. But he doesn't spend a lot of time with her (he works a lot of 13 hour shifts) so I feel like he's not that attached to her and he hasn't quite built that bond just yet. She loves him so much, though. Can anyone else tell me if they have felt like this, or am I going crazy lol