how to adjust values in vertical axis of line chart and include an entry on the horizontal axis

Hi all 🙂 I'm having problems getting this data set into a line graph:

Date E. coli Count

when i select the data set as directed, the line graph (which is what i want to use) looks like this:

as you can see, the vertical axis is automatically doing a 20k increment, which basically leaves out all the results under 20k, which i want to show, and plots them as 0 values :(.  also, the graph automatically added all these months where no tests were conducted (?) and the date of the last tests is missing entirely.

when i try to change the vertical axis increments to show what i need, it comes out like this with all the values mushed together at the bottom:

this just seems like it should be so simple!!  I've used excel graphing for over 20 years but i can't figure this one out 😞 Any help would be very greatly appreciated 🙂