I have one year old twins and a just-turned four year old. I was so sick every minute of every day of the pregnancy with my oldest that I was on Phenergan just so I could get and keep something in my stomach. (They tried me on Reglan, but it was completely useless.) With the first pregnancy, my heartburn was so severe Tums was also completely useless. My OB wouldn't let me take Prilosec, but Pepcid Complete became my best friend. (And in the last trimester my OB gave me permission to exceed the dosage.) Twins run in my family and extreme symptoms like the nausea are the result of a whole lot of pregnancy hormones so everyone (including my OB) thought the first one was a twin pregnancy but it wasn't. My second pregnancy started out with the same severity of symptoms as the first, and it WAS a twin pregnancy. Fortunately, the nausea eased way back after the first trimester (which it did NOT in the first pregnancy) but the heartburn was just as severe. You're not feeling movement, yet. (Even with twins, you probably won't feel the babies move until close to the fourth month but as they get bigger it feels like you're carrying an octopus. My first son was in CONSTANT motion and I thought it was like carrying octopus, but my twin whirlwinds taught me different!) The movement you're feeling is almost certainly the result of your extreme gastro-intestinal distress. If I remember correctly, the Reglan doesn't actually quell nausea the way Phenergan does, it works to empty your stomach quickly (which usually helps reduce the nausea) so this is probably what's causing you to feel like your insides are doing the cha cha! I'm not sure about your weight gain. I'm trying to remember if I put on weight quickly, but I just don't know. My breasts and belly expanded rather dramatically very early on.
You don't mention your age, but women in their early thirties are more likely to have twins than at any other time. If you're around this age AND given the severity of your symptoms you might be entering the world of "moms of multiples!"
Are you really worried? As in, you're concerned about being pregnant with twins? I was worried too. Not about adding two more to my family, but I was scared about being on bed rest and having to neglect my oldest or having low birth weight babies who would spend months in NICU, etc. Happily, twin pregnancies are usually fine. They generally arrive at 36 weeks - which is earlier than a full-term baby but is NOT premature. (It's actually considered pre-term.) And you need to have VERY frequent ultrasounds to make certain the babies are growing at the same rate, but I had a very healthy pregnancy. I never ended up on bed rest. I went into labor just after the 36 week point and delivered 6 lb and a 5 lb 9 oz
boys who were perfectly healthy and who were ready to go home before I was! The first three months were harder with twins than with a singleton, but after that it gets easier. Now, that they are one year old it's actually easier than a singleton because they are so interested in playing with each other! If you find out you're having twins (or even if you're not), please feel free to shoot me a message if you have any questions or concerns!