Quick Question...Please Answer

Okay today i decided to measure my waist and hips to see if i had gotten anywhere. Well to my surprise i have lost 1inch in my waist and hips as well. I was so excited so i thought i should weigh myself since i did well in measurements i may have dropped some lbs to. Big mistake! it has been 2 weeks since i last weighed myself and it said i gained 3lbs! I didn't weigh myself naked or on an empty stomach so i don't know if any of that could have contributed to weightgain. I have been jogging/fast walking 4miles almost everyday so could that have me gaining muscle and that could be why? Any ideas? Lol Help!-Clare I have actually been eating really well and most nights not past 8pm. what could it be?