I'm 10 weeks pregnant and have no desire to have sex, is this normal?

Yes, it's not unusual to have a low libido during pregnancy in fact; it's quite natural to experience fluctuations in desire due to the onslaught of your pregnancy hormones. Be reassured though, that this may change throughout the nine months.
Typically, sex drive tends to be lower during the first trimester due to tiredness or symptoms of morning sickness, can improve during the second, as you experience renewed energy but may drop again in the third trimester as your belly becomes larger and you prepare for birth.