Adding on?

We're hoping to start trying soon for another baby. The original plan was to leave a gap of 3 years between kids, but given how long it took to conceive him, it seemed smarter to start a little early. He's 19 months; if we got pregnant right away in July, he'd be 2 1/2 when the new baby was born.

I'm a little excited, but more scared than anything else. My first pregnancy was an utter, miserable disaster that ended at 11 1/2 weeks. My pregnancy with Moose was healthy and mostly uneventful, but it was still pregnancy, and I was tired a lot and pretty much down for the count by the last couple of months. The Engineer works a lot, and while we live near both our families, I don't trust them and am mostly on my own caring for Moose. I worry that I won't be able to take care of him while I'm pregnant, much less after the baby's born. I don't know if I've posted on here about my delivery and recovery from having him, but it went less than smoothly. There is absolutely no way I can think of that I'd be able to take care of a mobile but not independent toddler if I have problems like I did last time. I know people have done it, but I don't know how.

I'm also worried that I'll miscarry again. I don't know if I can handle that, either. I had to hide my pregnancy with Moose from everyone but my husband (and OS, of course) due to family issues after I lost the twins. That meant that not only did I have no support for the first third of my pregnancy, but I wouldn't have had any either if things had gone wrong. I would've had to hide everything--physical issues, grieving, any references ever to the fact that I'd been pregnant--because losing a baby without my father-in-law knowing would be the only thing more disastrous than losing one in the first place. Of course, not having told family for 12 weeks is also a crime, but whatever.

I worry about ruining Moose's life--particularly his sleep. I'm totally horrified that the baby will wake up many times a night, or maybe decide to be awake all night screaming, and will keep Moose from getting any sleep. They would share a room after the first month or two, and while Moose was a great sleeper and very easy on us, it took him a year to really settle down to the point of rarely waking ever up at night and going to sleep quickly and easily. I can't ask for better, but what if the new baby's harder?

I worry that there will be something wrong with the baby and that our current family and I won't be able to deal with it. I feel like we lucked out with Moose, allergies and surgery and all. He's a wonderful, happy, mellow little man. I love him. I know I'd love another child just as much, but I worry that there will be difficulties that won't make it as easy.

Yeah, I worry a lot. It's my thing. You've gotta do what you're good at. I can think of lots of great reasons to have one kid and call it good, but I'm having trouble thinking of any reasons for having more than one.

All that said, I do want more kids. The Engineer has been hinting at having another for a while (and his family has been outright demanding it for years), and the need to be pregnant again, biological or otherwise, has really hit me hard. I'm just...worried.

Can someone who's been there and had it work out please tell me that it's all going to be okay?