Why is my iPhone doing strange things?

My iPhone 6 has been doing weird things lately. Earlier today, my music from my iTunes was erased and the only music left were the preloaded songs. Also, while using iMessages, the texts on my screen will send and then suddenly fade; however, they are properly being sent to the recipient. I'm also not receiving notifications for my texts, and my text 'history' with my contacts have been erased as well. My apps tend to crash more frequently, too. The phone is low on storage, does this mean that I should clear up space by deleting items to resolve this issue?