Advice about my rainbow baby

Ok so we found out yesterday that I’m pregnant I’m about 4 weeks so only just pregnant. I’m elated however only in December I had a chemical pregnancy. I’ve had two other miscarriages years ago. I am just so shocked that I got pregnant so quickly. I didn’t realise I could. I am very happy about being pregnant, it’s just I didn’t get a chance to grieve properly for the one in dec. I feel like I’m betraying the other baby (I know it wasn’t a baby, it was an embryo, but to us it was a baby) I feel like I’m replacing it. I’m scared it will happen again yes, but I feel more guilty that anything. Anyone else experience this?