No connection to pregnancy and sad ☹️

My second baby we tried for so long through infertility battles and she was very much wanted- awaited rainbow. Now I’m newly pregnant 9 months after she was born and it was a complete one time ‘accident.’ Me and my husband have been on awful terms the last 6 months and I actually moved out. I’ve never felt more alone. I want to be happy about this pregnancy but I’m seriously scared. I’m honestly so busy with my other two kiddos that I kinda forget I’m even pregnant. My daughter doesn’t sleep well and I still breastfeed. I run on no sleep and never get any time to myself. I haven’t told anyone I’m pregnant except my husband cuz no one will be supportive of it. I’m awaiting my first scan at 8 weeks which is soon. I’m hoping I’ll have some sorta connection soon. I just feel so sad that I’m not really happy about it. It’s not the baby’s fault. I have no doubts I’ll love this child just as much but I just feel strange about it all.