Temperature - please help!

My 15 month old just had his shots on Friday. Last night he started to get a fever and now today has had a consistent 101 fever. Not sure if this is still from the shots or if he's getting sick? I feel so awful for him! We've given him Tylenol to hopefully help him keep the temp down. I'm going to to try and monitor his temp through the night, but I'm so scared it will spike really high and I won't know. He's kind of been coughing too. Pretty loose with runny nose.