Like TF9 says, its a bit early to panic. Always depends on where teh goals come from, too. And who against. I see 3 against Swansea, which is a reasonably talented attacking team. Giving up 2-4 goals against Man City or Chelsea shouldn't be horribly worrying, especially away. Are the goals from open play? Set pieces? Are they second half goals after you take big lead in the first half? Stuff like that can be related to half-time team talks and/or substitutions. Could also be late-match goals after your FBs get tired (especially if you haven't got a backup for Clyne).
The Southampton CBs are not world class, either. Alderweireld and Fonte are pretty solid but not the quickest. Yoshida and Gardos are not really upper Prem level players, at least at the start.
The Southampton CBs are not world class, either. Alderweireld and Fonte are pretty solid but not the quickest. Yoshida and Gardos are not really upper Prem level players, at least at the start.