Hi there and welcome to the weightloss forums.
I am like you in the sense where you start eating right or a different diet, do great but then fall off the wagon and put all of it if not more weight back on. Weightloss is such a hard thing and finding the inspiration and motivation to loose it is just as hard.
I agree with Cat, maybe check out the 12 week challenge and join up. It is ok if you join a little weight but it is a good thing to do to motivate you.
If you need to chat, I am more than welcome to.
Stay strong and positive. Good luck