Collins Russian Dictionary 2nd Edition © HarperCollins Publishers 2000, 1997:
стра́шно нареч (кричать) in a frightening way; (разг)(усталый, довольный) terribly
как сказ it's frightening
мне стра́шно I'm frightened или scared
стра́шно поду́мать it's frightening to think
он стра́шно дово́лен собо́й (разг) he's awfully или terribly pleased with himself
она́ стра́шно уста́ла (разг) she's awfully или terribly tired
она́ стра́шно лю́бит болта́ть (разг) she really likes to chat