stopped taking CrEaTiNe

I stopped taking creatine about 1 month ago and lost 5 lbs. Im 5'8'' 157. My question is.
Is this 5 lbs most likely water weight?

Most likely it was water and electrolyte weight. Creatine retains both of these.

Does creatine really even help for weight gaining?

IMO Creatine works more to promote strength gain than muscle mass gain, but moving more weight causes your muscle mass to increase. Thus, in a round-about way creatine will help increase muscle mass.