possession

Many thanks for your time. I indeed failed to take account of the pawn's vulnerability after 7.Nd5 and with my opponent noticing the possibility of a fork, the entire of the Queens side has been pretty much locked up. I fear that after my errors in 7.Nd5 and 8.c3 the best I can play for is a draw. Is it generally better if you are down a minor piece to try and play for further exchanges so as to reduce the eventual mating power of the opposition or does this just serve to amplify the impact of the material discrepancy? ps. On your two points you will see that I am now registered and I should note that in the game from which these questions are drawn, both me and my partner are consulting with others (we are but humble novices in need of guidance). Though I agree I have probably gone one step further than he will have by consulting with someone above master level!