Working out for almost 3 months but gained weight? Weights and cardio 3-5 times a week...HELP?

I have been working out for almost 3 months now cardio for an hour 3-5 times a week and weight circuit 4 times a week and I've GAINED weight. I don't know what I'm doing wrong! My cardio is kickboxing, spin cl and aerobics. I don't know what to do its getting so depressing! I've gained about 3 pounds since. The only difference I've seen physically are my legs are a bit thinner. How long does it take to see a weight loss? My eating habits are ok, but could be better but its not like I changed anything from before when i was maintaining? I am 24, 5'1 and weight 135! pounds as of tonight.. ugh. Any input please. How long does it usually take to see results on the scale