Wheat has gone through a lot of weather change in the last 10 days. Most wheat should be coming out of a water logged state (see photo below). This week will give a a really big change in the way your crop looks.
Now is the last chance to top dress before jointing (you are really three weeks late). Think about mixing 1,000 lb. of UREA and 1,000 lb. of Ammonium Sulfate per ton. This will make a 35-0-0-12 sulfur. This is a great top dress for any small grain. With the rainfall we have had most of the Nitrogen and sulfur you applied has leached out of the current shallow root zone. It is still there but the roots need to get deeper to reach the N.
If you are concerned and have already put out 95 to 110 lb. of N, then please wait until the soil dries some and the plants send up flag leaves. This will probably be around April 1.
Tissue test your FLAG leaf, do not get the largest in each plant as it will get the first choice of N in the plant and give you a reading on it only. I prefer to get one from the smaller tillers because that is where your yield will be increased. These smaller tillers will dry up if you do not have proper fertilization.