You are not a slacker if you miss a workout, or if it is like pulling teeth to get through a workout. We have all been there. There are days that are just hard and suck but the thing is, you did a workout, or if you didn't you did the next day. You must keep going and try again. And if you did your workout I bet you feel a heck of a lot happier after the workout than when you started.
If you haven't found the workout groove yet and just can't find the motivation, that's ok too. It will happen. It takes hard work but the first step is always the hardest because that is when you decide that you want it! And when you go YOU WORK HARD FOR IT! And do it because you, yes you, are so worth it!