Hi, I Am 20weeks Pregnant And Was Prrescribed 2 X

Hi, I am 20weeks pregnant and was prrescribed 2 x 40mg dosages of clexane for a flight 9hours and another connecting flight of 6 hours. I did take the first shot, but not the second one, I was supposed to take that the day before yesterday at 10:30. Can I take it now, or should I leave it? I have walk quite a lot since arriving at our holiday destination. Just so worried that a blood clot could develop. My dad has had a few blood clots before. Thanks in advance.