Pains in one leg- anyone else had this?

[Newlywed56]

I'm 20 weeks and on Christmas Eve I started getting pains in the back of my thigh and calf in right leg only, just put it down to cramp. However 4 days later still hadn't really improved etc so phoned the out of hours gp who recommended a&e for blood test and possible scan to rule out blood clot. Bloods came back fine but they still did a clexane injection at 1am this morning then have to go back for another one late tonight and scan tomorrow . Just wondering if anyone else had this? I think they are just airing on the side of caution as bloods were ok but is obviously a bit concerning.