Just because you aren't losing weight doesn't mean you aren't getting fitter. It can even mean the opposite. You can tell by the following signs that you have definitely become fitter.
In the beginning, you may have had trouble keeping up with certain exercises. If it gets a little easier, that's a good indicator of improvement. Don't worry if there is a training that went downright crap, off days are part of it every now and then.
When you finally take the step to start strength training, you can quickly see progress. Don't panic if it seems to stop after that. It is normal to make a lot of progress in the beginning and then it seems to slow down. If you compare, you're probably already holding the weights up a lot easier than when you first started.
This can be misleading, because your clothes don't necessarily have to be looser. If your buttocks or thighs become more muscular, your pants can get a little tighter.
Exercising not only provides energy during the day, it also ensures a better night's sleep. Check which training you do when. An intensive HIIT just before going to bed will most likely not ensure a better night's sleep.
That's a question you can answer for yourself. For some people, it helps to occasionally use the number on the scale as a guideline. Do not step on the scale more than once a week. Prefers to choose a fixed time during the week.
Martine Jacobsen