"I haven't slept very much" sounds quite natural. For the others, I would suggest: I didn't get much sleep last night. OR I haven't gotten much sleep lately. I didn't sleep very well last night. OR I haven't slept very well lately.

You need to say "well" instead of "good". You need an adverb to modify the verb "sleep" rather than an adjective like "good" which is not capable of modifying a verb. Present perfect tense ("I haven't slept") and past tense because ("I didn't sleep) are both acceptable. If you want to emphasize the way you feel right now - the fact that you right now are a person who hasn't had enough sleep - then use the present perfect. I would say it thus: "I didn't sleep well."

There are differences in meaning. I didn’t get enough sleep. (Not long enough for me to function my best) I didn’t sleep well. (Maybe the length of time, maybe a poor quality. Judged on an absolute scale) I didn’t get my full night’s sleep. (Last night, I expected to get a certain quantity, but didn’t. It could still be enough. It could still be a pretty good night’s sleep. It might not be) ‘I haven’t slept very much’ could be natural but is a little more ambiguous as to the time period. I’d be more likely to use it if the period of time is longer. Since my husband lost his job, I haven’t slept very much. I lie awake at night worrying about our finances.

Hi Pelin, I haven't slept very much. This sentence is correct! I usually add a phrase to give context: I haven't slept much these days. I haven't slept much lately. I haven't slept much because I have a lot of work to do. I use these phrases to talk about my lack of sleep or my poor sleep habits. I didn't get enough sleep. I didn't get much sleep last night. I didn't get a good night's rest. I didn't sleep well last night. I haven't slept well for a while. I hope this helps. English is fun to study and you asked a great question. Speaking naturally is an interesting concept. The more you use English the more it will be natural for you!! Everyone has different ways of expressing an idea, a concept or a thought. Because you asked this question you are on the right track because those phrases didn't seem quite right to you. Happy studying!!! Best regards, Martha