Do these mock up veneers look too chunky for my face? (photos)

Since you always have seen yourself with the spaces between your teeth and now that the spaces are closed your smile look bulky to your eyes. From the pictures that you posted they do not look "chunky". Also the final veneers are a lot finer and smoother than the temporary mock up. However if you are still unhappy with the mock up it is better to modify the mock up before going for the final veneers.

I think the mock up is a nice improvement! Because your not used to seeing yourself without the gap and bigger teeth, they may feel chunky and big. 
I do think the teeth are a little too square and could benefit from some rounded incisal edges. You hardly see the bottom teeth when you smile, and I think they blend nicely with the mockup!

You have had more rectangular teeth in the past and the mock ups have added more feminine curvatures.  This may be needed to close the gaps, somehow the teeth will have to get larger to do this if utilizing veneers alone.  You could request the dentist to make the mock up veneers slightly less curved or more square if possible to see the difference but I kinda like your new smile contours.  It is a very personal decision and you should be comfortable with the shape.