I have had influenza, this is third week and much improved except very week and tired and a heart rate of 127 when sitting down should i be worried ?

Too fast: At your age (I'll keep it confidential), that's not a healthy heart rate for you. It's likely that you are dehydrated since you've been ill. I assume you no longer have fever (?) which could also cause rapid heart rate. Force fluids until you're urinating clear urine frequently. If your heart rate remains >100 at complete rest, seek medical attention - you may have an arrhythmia like atr.fib.