Infusion treatment

Just wondering. Sometimes when I get my infusion seems to work fairly well then other times feels like it's not helping at all. Anyone else have this problem. I'm sure some do but it gets tiresome. Had my infusion 10 days ago and feels like I didn't get it at all. Currently on Inflectra every 6 weeks. Sometimes I wonder if it's age related too. I'm 59
Any thoughts?