I just started using Humalog and didn't really get any instruction on how to use it. I wasn't told to use it before meals or after. I was given a slide scale on the units to use. 0 to150-0 units, 151 to 250 3 units and so on. When I got done eating dinner tonight I took 3 units of Humalog and two hours after eating did my sugar and it was 199, OK, something is wrong here. What can I do or am I doing something wrong.