This Really Is A Solitary Bee :(

I have an area in my back 'lawn' that has lots of field bindweed. This time last year the flowers were absolutely buzzing with insects. This year, because I'm doing no mow summer, the flowers have appeared but are twining up the grass stems. There must be hundreds, if not thousands of them. Even though I looked very carefully I could only find one flower with a bug in it. I haven't been able to identify this tiny solitary bee. I find this situation very worrying. I'm guessing it's to do with all the wet weather we had earlier in the year.