Speech problem, what's wrong with me?

I'm 16 years old and have had a speech problem for as long as I can remember. Recently it has gotten a little worse.

I am lost and don't know what to do, it effects my every day life and I need to fix it.

I don't really stutter, but I have a lot of blocks on certain letters, mostly I, w(what)(when), and more.

I feel like my vocal chords just won't open and sometimes I just give up and stop talking.

It's much easier to talk to a family member or a close friend, anxiety makes it worse but even when there's no anxiety It still happens.

Recently I have noticed that my speech has been slightly slurred and my mouth has felt odd.

I've been almost skipping parts of words, mixing them up, for example instead of saying freezer section I would say freesher shection and sometimes I try to talk really fast and it doesn't come out right.

It's easier to talk when I'm relaxed.

This problem is making me really depressed and causing me to avoid social situations.

Please help me