Hi WaterBird!
Is the primary problem with staying awake or a wandering mind? If it is staying awake, I would continue to meditate in a seated position and try to do your sessions when you are most alert. I think you will gradually extend the time in which you are consciously engaged.
If the mind is wandering, there are a couple of things you can do. If it is coming up with things you need to attend to, you could stop your meditation, write down what is coming to the forefront and acknowledge that you will deal with those issues later. Often just the acknowledgement and promise to deal with things at an appropriate time will pacify the mind and it will step aside.
If the distraction is just a general wandering, you can acknowledge what is being presented, thank your mind for sharing and then return to the meditation. If you do well with visualization, you can imagine the thoughts as clouds in the sky that are just floating by or leaves on a stream that are gently bobbing along and out of sight.
I have a friend who started telling her mind that a tour bus was waiting to take it on a wonderful trip and she would be there when it returned. Once her mind was on the bus, she would start her meditation, and when you was done she would tell it that she was back. After the first few sessions of following this technique and purposefully re-engaging her "everyday" mind when she was done meditating, she had no further problems with unwanted intervention.
In this case, it seems as if a relationship based on trust had been developed and that might be what we all need when the mind keeps intervening. "I'm asking you to step aside now, but you can count on me to acknowledge you as soon as I get back." Maybe that's the bottom line in all this - we need to build that internal trust. So many of us are far more trustworthy to others than we are to ourselves. Maybe the ego (as represented by our mind or internal dialogue) doesn't yet trust us to keep our word to ourself. Food for thought!
At any rate, try the above and see what works (and let us know)!
With love,
Wendy