Devo

Yep, you got it, tip stall. The key is, you said you took it around for a slower landing. The flight controls need to have air moving over them to have any effect. You may not have felt as though you panicked, but in effect you did. You froze at the controls. You just kept holding up elevator and watched as it dove into the ground. What you needed to do at that point is let the nose drop with a neutral elevator and gain some airspeed then try to recover.

Try to carry more speed into your final turn and let it slow as you come in with the wings level.

Don't let yourself get too discouraged. Try to learn from what happened during your first flights. The first 4 days seem pretty obvious, avoid the things that caused those accidents. Never take off if your engine is being finicky. Chances are, if it's finicky on the ground, it'll die right after take-off, or soon thereafter. The ground loop thing is just a matter of practice. I'm sure you know you need to extend the antenna, that just sounds a little like a case of the butterflies to me.

Anyway keep at it. It doesn't sound all bad to me. You had the confidence to solo a lot sooner than most people do. Just learn from your mistakes and don't be embarrassed to use that trainer cord. Good luck