first of all, congrats! you should go see a doctor and get them to help you get into some anti-natal classes. they are really helpful and they tell you all about what will happen to your body and how you know you are in labour etc. its really important to know so you dont get scared or so you know warning signs etc. ultrasounds are normally pretty accurate... especially at 28 weeks. also try look out for mums groups around your area, you will get a lot of support from them and make some friends in the same situation as you... i hope everything goes ok

keep us posted on how you do ok?