Nothing Special

My flowering cherry has only a tiny bit of blossom on it.  It is so disappointing as it's about 10 years old now.  I planted it in memory of a wonderful flowering cherry I had at my previous house, which I had also planted myself.  But this one - every year I get about four bits of blossom, and then the red leaves which should be abundant, start to shrivel and die.  It must have some sort of disease - each year I read up about it and try to do things to help it, but to no avail.  I don't know what to do next.  I can't bear to kill it!