First foremost congratulations on your second pregnancy. Don't feel the guilt and feeling bad over things that has already happened. My advice would be to speak with your spouse because end day emotional support is important. When you make love it takes two hand to clap, so when you are pregnant he needs to know and be there too.
Slowly when you are few months ahead example : second trimester, then you break the news to both of your parents.
Don't think about what others said. Ignore. Think of those TTC parents trynna conceive but they are not able to. Be thankful we are the chosen one. Though it should have better be plan like you mentioned. There's also a reason why doctor advice us to get contraceptive soon because whatever we do, one way or another we may get pregnant unexpectedly. After birth, we will definitely have healthy egg follicles hence why it happened.
My sister conceive her 4th when her 3rd was 4 months old and she just had her C section 🤷🏻♀️😅 (tell me about it, the ouchy pain). But, she embrace it till birth and now he is 1 years old.
Definitely, it will take awhile to digest and process it all. But sooner or later, you will feel better and feel happy. Try to divide the attention where needed.
All the best mummy ♥️