I had an abdominal u/s during my 5th week, saw a sac with a little dot in it and what might have been another sac. DH was excited that it might be twins, I was skeptical, thinking it was way to early and it was an abdominal u/s at that. The next u/s was in the ER when I was bleeding, I thought for sure that I was miscarrying. The doctors saw one healthy heartbeat and what appeared to be a sac, but didn't see anything in it. The very next day I was scheduled for a radiology u/s, I was 7 weeks at this point. There, just one day after only seeing one baby with a healthy heartbeat, I saw two little dots with two healthy heartbeats. The bleeding was the cause of a subchorionic hemorrhage, it didn't hurt the pregnancy, but scared me every day for 5 weeks while I bled. lol So, even as late as 6w6d pregnant, you can see one baby and not the other and the very next day see both. It really ALL has to do with the type of equipment used. The radiology department had a much better machine than the ER.
As far as only wanting one and you might be getting two. Well, it can be difficult to swallow. We were in no way ready to buy two of everything! However, if that is what you have to do, you find a way. We got a lot of brand new or like new items from Craigslist or friends. It's amazing what you can get for free too! If you only have the money for one crib, that's fine, twins do better together anyway, I am sure you have heard the term co-bed. They say it helps them develop better. If you can't afford a crib, there is always a pack and play with bassinet that works too. My twins are two months old and still using that together. Of course, they are about to go in the crib now that they are sleeping through the night. It will be really hard on you though if DH doesn't get excited about twins if that is what it turns out to be. Hopefully he can accept it and be happy about it. Your pregnancy will go by a lot smoother then, because towards the end, it can be rough on you. I have experienced one baby and twins now and I can tell you, that with a good supportive husband, two is no harder than one.

And when you have to do it all on your own, you quickly adjust and find a way to care for both of your babies. So try not to stress too much the fact that there may be two in there.
I don't think lack of sleep will hurt your baby or babies at all. It only hurts you really. Try to figure out how to get some rest. Your baby(ies) will do great in there no matter how much sleep you get.

Just try to enjoy the pregnancy, after all, you worked hard for it right?
