Can't do anything useful in dreams...?

Hi guys, I'm new to the forums, and I joined because I need a little help. I started trying to lucid dream several years ago, gave up, and now I'm giving it another shot. I've had a little bit of success, but I'm having some weird problems.

The first is the topic. Once I'm lucid, I for some reason can't do anything useful. It's like I'll say, "I'm dreaming right now", but I have no inspiration to do anything. It's like the dream is telling me the opposite of what I know, effectively rendering my knowledge useless. I can't figure out what the problem is. Has anyone else ever experienced this? Any advice on how to shake it off?

The second thing is less important, but I think it's worth mentioning. Once lucid, I have tried several times to fly, but I'm having tremendous trouble with it. I know it's important to believe you can do it, so I even chant to myself "You can fly, you can fly!". That helps a little bit, but if I manage to even get off the ground, I always feel very heavy, like I'm going to fall down, and I have trouble staying up and controlling my movements. I have similar problems with other "impossible" tasks. Any advice?

Thanks in advance!

Just go with it, your dreams have purposes. I had these problems too, personally though I didn't really care just being in a dream was good and interesting enough, the thing is you're not really convinced you can fly you need to try passive control look it up on this forum. Also for lack of purpose try becoming more aware and try to increase vividness in your dreams that should help, you can PM if you have any questions.