I am not going to tell you what to do because I am new here and know next to nothing about you. More experienced people will come through I am sure.
One of the great things about crosfit is how scalable it is. If you go in and cannot do a pushup then there is doing pushups on your knees, on a box or the wall. Scaling is important. I do not have to be as strong as the games athletes or the guy next to me. I just do what I can so I can be back another day.
CF really isn't that complicated and scary. The coaches are there for a reason and not once have I felt off about asking for assistance or asking questions regarding what to do.
As humans we are made to adapt and if not we die.