Potty Training Set Back

Today has been not so good with potty training. Charlee has been potty trained since October with only minimal accidents, usually playing and not wanting to take the time to go potty. Today, Charlee had 4 accidents, three at school and one after dinner. I'm not sure why....Here are my theories:

1. Could she have a bladder infection? She says it doesn't hurt to go pee-pee.
2. Could she be constipated? Possible. She said her tummy hurt this morning and after dinner. She went poop but it was 5 hard rocks. Lots of applesauce and water for dinner.
3. Could it be a control issue? This is always a possibility.
4. Could she be coming down with something? Another possibility. No fever. Ears have wax build-up so I put ear drops to break up the wax. No red throat but nose is running and inflamed inside. She has one swollen lymph gland on the right side of her neck. This might be the winner. I gave her some decongestant and saline nasal spray.
5. Could she be teething? She doesn't have her two year molars but I could see any signs of eruptions.

If I'm missing anything, please tell me.