not pumping enough

So these past few weeks how much I pump seems to have been going down, and today I’m not sure I’m going to pump enough for bottles tomorrow (I work full time). I don’t understand why. One hunch I have is I might be ovulating (a few of the typical signs) but I haven’t had a period yet. I really don’t want to stop bf, my goal was 9 mths to 1 year. I hate pumping but love nursing, although working full time has proven to be tough. I don’t think it’s like how much I drink or anything. The one thing I have changed is that I stated working out, and he has started solids but I didn’t drop a feed - I feed him solids in the morning after nursing. Anyone else going through something similar or have advice? He also seem agitated during our bedtime nurse lately.