i finding alot

i finding alot of wonkiness is happening for example when i save a project then go the site to check it my pictures disappeared, or when i set my links in the menu they work fine but again after saving , other fails so fix one the other one is not working and my canonical.php is saying multiple errors and my resource usage is almost is almost full, Any suggesting i've been trying to fix by minification,compressing ,i've even shut all plugins one by one and scan shows no malware so can you point me somewhere, please.