I was wondering if it’s considered haram to kill mosquitoes? I saw one in my room and I instantly made the choice to kill it without thinking if it would be considered haram to do so? It wasn’t harming me but was flying around my room and I was worried it would bite me while I’m sleeping.

There is nothing wrong to do that. We have full authority to protect our body from any threat either by diseases or by insects or anyother threat.