What exercises have changed over the last 6 weeks?
I have an on-line client that started doing deadlifts only a couple months ago but has always done heavy rows. A couple weeks ago he pulled an easy 705 but then it went down hill greatly while getting ready for his upcoming meet. I'd told him that from looking at his rows and his deadlifts...his rows were his BUILDER exercise for his deadlifts, maybe more than any other exercise for him. He does rows first before deads and had greatly cut them out for about a month so he would be fresher to pull bigger weights. He did pull bigger weights for a few weeks, then his pull got harder and went down. Something to think about...
And if you want to do curls...do curls. It's really important to make progress in the gym and be excited. This is why I always add in and out bands, chains, etc... Stuff is always changing all the time keeping me excited to do different stuff. Add in the briefs, suits, shirts, etc...and I have that many more options.