Meghan's plot is about to be complete. Timing is key here. She gets rid of you and marries your fiance. She got inseminated by your bf 3 months ago. When did you get engaged? Months ago? I would not be surprised if she did not plan this when she first heard of your engagement. She must've been fucking furious. 

She wanted to ruin it for you BEFORE you got married. The pregnancy is her last and desperate attempt at getting back at you and getting back her "friend". That psycho bitch is on track. 

Get out of this relationship asap, let karma bite their asses and believe me it will big time and for a long, long time.