Hi and congratulations on your pregnancy

I did not find out I was having twins until 21 weeks, but the symptoms I had which should have warned me were:

exaggerated pregnancy symptoms (fainting, MS, etc)

bump showing very early (was my 4th pregnancy though so to be expected)

kicks starting at 11 weeks

lots of kicks, simultaneously in ribs and cervix by 20 weeks

Twins running in families - well it cannot come to you from your husbands side as twins (non identical) are dependant on you releasing 2 eggs. They say it can skip a generation, but not two. So it doesn't sounds like you have a raised risk factor genetically. However I didn't either. The number of pregnancies you have had raises your risk of twins, and the older you get the more likely you are to have them too. But a lot of the time women don't have risk factors and just get lucky

If you are having twins, please be reassured that finding out later still leaves plenty of time for planning. If you are healthy there is not really anything different they would do with your right now anyway. By now a midwife is more likely to be able to have a listen for a heartbeat/heartbeats but IMO you should put your at home doppler away as more often that not they cause false worry, or even worse false reassurance.

I hope you find out soon

trav
xx