¡Hi Marcin! The right sentences are: "Tengo miedo de hacerlo" and "Temo hacerlo" You could also say "Me da miedo hacerlo" "Tengo miedo hacerlo" isn't correct. To say "I was considering doing something" both "Estaba pensando en hacerlo" and "Estaba pensando hacerlo" are right. Another option is "Pensaba hacerlo" I hope it helps :)

Both temo hacerlo and tengo miedo de hacerlo are right. However, tengo miedo hacerlo is not. About whether you have to use "en" or not, you can ommit it, it'll sound very natural this way.

Hi. The correct prepositions to use after TENER MIEDO are "DE" and "A"; this means that you have to say TENGO MIEDO DE HACERLO. another example could be TENGO MIEDO A LAS ALTURAS. On the other hand, TEMO HACERLO is correct, but it has a pragmatic difference. When you use this phrase, you mean that you fear the consequences of your possible action, and not that you don't have the courage of doing something. Regarding the use of EN or not in the case of pensar, they also have a pragmatice difference that can be seen in the following examples: - Pienso en hacerlo= I think about doing it - pienso hacerlo= I intend to do it