Can someone please help me with particle regonition and intensity analysis?

I am trying to find a way to recognize particles I have and subject them to intensity analysis, so I can plot their intensities on a graph. I have been following youtube tutorials, but the problem is they use different sized and shaped particles. Every time I try to recognize the particles, they seem to be picking up half the particle or a third of the particle I want. To show an example of my particle, this is a picture.

Basically, after uploading this picture I adjusted the threshold to huang. I then change the process to watershed. Then under analyze particles, I’m not sure what to use as the size and circularity. I think this may be the problem, as I’m not sure what size to use for these? Can someone please give me some suggestions? Thank you!

What about you use these values (macro code)?:

selectWindow("Screen Shot 2016-08-24 at 9.28.10 PM.png");
setThreshold(12, 255);
run("Analyze Particles...", "size=150-Infinity show=Outlines display exclude include");

I get this result:

Do you need your particles to be closed?