I did the exactly the same thing when i was pg with MJ, we werent trying, so when i got some cramping i thought that i was going to get AF, so i took Voltaren (which is significantly stronger than Nurofen plus but has similar actions) I also had a cold, so had ben taking Cold and flu tabs.
Well, i did a test the next morning after the Voltaren as i dreamt i was pg and i was - i was really scared, so saw the pharmacist as they know about how all the drugs interact better than anyone and he said that the way that it would harm the baby would be a m/c and it would happen fairly soon after taking them (1-2 days)... and that the Voltaren was more of a concern...

I dont know if this is completely correct but this is what i was told and i was in a similar situation to you, so thought that i would post.

Congratulations on your BFP and i hope that its a sticky one