It should be "上去" and"下去".

i want to go up and i want to go down better to translate 我想上去。 and 我想下去。 pick me up one explanation is 去接我, but this phrase has also other meanings. put me down 放我下去 phrase can have different meaning which can not be translated directly, so if u r confused, please turn to the help of dictionary. i believe that is also a good idea.

上 下

我要上去 我要下去 把我带上 把我放下来

i wanna go up/ 我想上去 or 我想上来 i wanna go down/ 我想下去 or 我想下来 pick me up/ 来接我(if you mean pick someone up by car for example); pick me up/ 弄我上去(if you mean pick someone up to somewhere); put me down/ 放我下去