SharePoint online bad performance

Hi

The last couple of days I am experiencing very slow performance on my online SharePoint Site collections. When ever I create new items or customize features, it takes ages to save. Even just accessing pages or team sites, take for ever. 

I only use SharePoint OOTB, and I am the only user on thise site collections, as I mostly use them for testing.

Does any one else experience this or is it only me, and if so how can I see what is affecting the performance? 

I am Global administrator on my Office365 and Sitecollection admin on all my SharePoint Site collections.

I hope some one can help me.

Thanks

Maria