Am I a bad person?

My boyfriend had been planning a proposal for months....well 4 days before our planned date night, my period hadn’t shown up. The day after we announced our engagement, we found out we are pregnant. I’m almost 4 weeks. Don’t get me wrong I’m happy, but is it bad that there’s a tiny part of me really sad that it won’t be just us for a while longer? We’ve had so many plans for things we wanted to go out and do this year and now everything is changed. The guilt I have over this is insane. The first ultrasound will 182% change my mind on how I’m feeling now, and make me fall in love, but I feel so guilty until then.