Couple things it could be.
The most likely and also the most obvious is the frog isnt hungry. Bullfrogs eat a lot but even they do become full. If he has eaten heartily in the last couple days he may just not be all that hungry. I have many frogs or various types. I feed them 2-3 times a week. Some of them dont always want to eat. I just keep an eye on the ones that didnt want food and make sure they eat next time. If they do, great. If not then I will take a closer look and make sure everything is in order. But its not unusual for an otherwise healthy frog to refuse food from time to time.
Prodding the crickets into his face is not going to help. If anything it will make him less likely to eat. Im sure he sees them. He just may not want them. I would remove the crickets from the tank, wait a day or two and try again.
May as well go ahead and check and make sure the frog is in the proper conditions. Clean water, land area, maybe some hiding places, etc.
Now the bloating. More likely then not your frog is juist fat as everyone overfeeds their frogs (And snakes, and lizards, and kids, you get the idea). However there is an ailment that frogs get which causes bloating. Not too much is known about this. Some people think its an infection out of control and others think it can have something to do with the conditions the frog is living in. Its possible the water quality may bad, another good reason for cleaning the tank. Use dechlorinated water as frogs and other amphibians are sensitive to these chemicals. It could also be an impaction, something the frog ingested that got stuck. Its really hard to say exactly what it is. Hopefully hes just chubby.
If the frog appears ok and is moving around normally then hes probably just a little fat. If he continues to refuse food and looks even more bloated than he may be sick require further treatment.