Advice please? Fussy baby...

My LO is 4 months old and fussy. She doesn't seem colicky- she was when she was real little. Now the issue seems more that she can't/ won't sleep. She's been really fussy over the past two days. Shes fed, dry clean diaper and I've tried everything I can think of to get her to sleep. Usually she takes a bottle, I lay her down and she will go to sleep on her own. Occasionally I do have to rock her until she is sleepy enough, then I lay her down. I've been rocking her, tried putting her in her crib, walking around with her, tv( which is only used as a last resort)- everything. I've mostly tried to keep her in a dark and quiet room so she can rest better when it's nap time. If/ when she does fall asleep it's only for 15-20 minutes. She usually takes a 2 hr nap in the morning after breakfast and a 3 hour nap in the afternoon but lately she does good to get 15 minutes each time. I gave her Tylenol earlier- she seems to be teething and had a 1 degree fever. It brought her temp down but she is still super fussy.  I don't know what else to do for her. I know only being 4 months old, something is wrong for her to be this fussy. I will let her fuss for a minute or two in hopes she will calm down/ self soothe (which she usually does) but will not "let her cry it out" at this age. Any other suggestions?