I had aggressive turbinate surgery 2.5 weeks ago. no allergies and felt good for 2 days but now congested again and it alternates. is this normal?

Check with surgeon?: Since optimal healing after surgery takes about 6 weeks, it is not surprising that there may still be some inflammation and even crusting at 2.5 weeks. However if the congestion worsens or lasts beyond 6 weeks, one would need to rule out a sinus infection. Very aggressive turbinate reduction may also open up the nose too much to lead to a sensation of congestion called empty nose syndrome.

Normal...most likely: This is likely residual inflammation from the procedure that should subside with time, although there could be something new going on, such as infection, allergies, irritation, blockage, etc.. Best to contact the surgeon and discuss this, and likely just be seen to ensure this is normal.