I was on msten for a while, and initially I felt like nothing was happening for 3wks, however, when I decided to add more weight to see what would happen, I was actually able to lift it. For example, I was stuck benching at 275 for reps, then I decided to add 5lbs, 10lbs, 20lbs, then finally 30lbs (no joke!) all within 6wks from taking msten. But for about 3 weeks I was just waiting to feel something, but I didn't feel anything.
I know Halo is different than Msten, but maybe just try putting on more weight to the bar and see what happens? I never tried Halo so I don't know, but I also felt the "feeling nothing" feeling. When I went up in weight I didn't feel any pumps or anything, didn't feel like I had anything special in my system except for the fact that I could "magically" lift more weight.
Maybe this helps?