Can you fly when high risk?

Paige • 23- UK. Our little pea due November2017 ❤🌈🌞
I'm very over weight for me being pregnant and someone told me that if you are high risk pregnancy you can't go abroad? I just found out I'm pregnant the other day and I'm due in October. I'm due to fly out to Spain in June so I will be about 6 month gone and just wondering is this true? I'm panicking because we've paid loads for this holiday :(