I have had a turtle for about 2 weeks now, and today I noticed him laying his head against the glass, which I did not see him do earlier. I am quite new to reptiles and I am a bit worried. I have also noticed him being quite nervous when I try to pick him up. He did not do this before. Is this normal?

I feed him vegetables, bloodworms and dried river shrimp. I also dust them once in a while with calcium powder with vitamin D₃.