Ivig wearing off too early?

I am at 70 grams every two weeks and although I was improving I felt like the day before was not so good and the day after was not so good either. I had to skip a treatment to clear it out of my system to tak a blood test to confirm I did not have elevated SMA . So after two weeks and knowing I was going to skip an infusion I was waiting for failur to set in after 12 days it did not. It was nearly 3 weeks before I noticed the significant drop. I think I was over exerting my self a couple of days before my infusion be cause I new I would be limited in what I could do. And Tuscan causing the fatigue. When I kept my pace the end of week two was uneventful. Although the end of week three was horrible.