Umbilical Hernia due to pregnancy - Should I have another operation done?

When I had my first son in 2005 because he was a big baby @ 9lbs. 1 1/2oz. I developed an umbilical hernia. I had surgery done to correct the protrusion. I just had my second son 4 months ago and he weighed in at 9lbs. 15oz., much bigger than his big brother when he was born. I have a gut feeling that I may have developed another umbilical hernia [possibly in the same area] and I think it may have tore more because of the size of my second son being so big. Also, when I lay down flat on my back - and go to crunch forward/up [like going to do crunches] I put a finger right below my naval and I can actually feel my finger being squeezed between the torn muscle. So my questions were: 1) Should I have another surgeory to correct this problem... 2) Would it be safe to have another baby?