Not all is lost. In fact Letrozole can be a good product when used correctly - good for getting a hard look also with used with cutting stack.
It have a 1/2 life of 2-4 days with an effective dose of o.25 - 0.5mg per day. Above that can really mess up your sex drive.
Keep a check on cholesterol levels while on it.
It can have a nasty rebound but when used for a longer period of around 2 months this can be minimized.