Teenage weight issues, please help.?

ok see im 16 and i know people say that this thing im gonna tell u is not healthy and bla bla bla but see when i was 14 years old i was at 152 pounds and in 5ft that was alot so i decided that i needed 2 lose weight when my father one day said i was fat i never considered my self as fat i thought i looked good but now that i weight 119 pounds which means i got 9 more pounds to lose now im 5 ft 1 now i see i was a cow lol i seen pictures of me at 152 and i show them to my overweight friends to show them that they can do it. im curvy and everyone in school likes my body i get alot of boys but like i was saying when i decided 2 lose weight i tried that tea name 3 tea ballerinas i drank 2 cups everyday for a week and 4 days and without diet or exercise i lost 9 pounds them when i stopped drinking the tea and i saw my belly flatter i decided to have a meal a day for a month and it was like a sandwich a day and that's it that month i lost 20 pounds them when i started eating alot again i gained 2 pounds and listen i even ate alot of McDonald and muffins before bed everyone in my house and my friends were jelous that i always ate so much a never gained or lose a pound them i was trying to get down because i was at 134 pounds so i exercised everyday hard for 1 hour but i never lost weight and now im 16 and started to eat less than 900 calories and 2 days of a week ate whatever junk i saw and it was like 1400 calories for 2 days of a week and the others like 500 to 800 cal now im water fasting but the third day is hard and i always eatwhatever i want on day 3 them go back im tired of this i wanna be able to have at least 7 days on water to lose does 9 pounds but see i exercise 3 days a week sometime i walk like 4 miles a day when i cant exercise for 2 or 1 hour and see im down to 119 pounds and i have no health or metabolism problem i never gain the weight back so dont belive people that say u will gain it all back once ur off it could be just water weight u gain but that goes off or maybe a full colon so make sure to use laxative twice a week like weekends and u will have a flat belly with a clean colon trust me