I'm a sophomore and I feel behind

Time itself, and only in one specific sense: a commitment held for three years cannot be created in one. That is the honest limit, and it is the argument for starting something now rather than waiting until you feel more organised.

Relationships with teachers are similar. The letters that say something specific come from teachers who have watched you work over more than one term. That is not a thing to arrange in junior spring.

Pick one thing you would still want to be doing in two years, and commit to it properly rather than trying it. One is enough. It is more than enough.

Then look at next year's course options honestly — not the most impressive schedule, the hardest one you can carry while keeping your grades up. Those are different, and confusing them is the most common way a sophomore makes junior year worse.

Everything else can wait. Feeling behind usually produces an urge to fix all of it simultaneously, and that reliably produces nothing.

If this question is keeping you up, that part is worth taking seriously on its own terms, separately from anything about college. Being anxious about the future at fifteen is common and it is not evidence that something is wrong with your plan.

Talk to someone — a counselor, a parent, a teacher you trust. Not because your plan needs fixing, but because carrying it alone is harder than it needs to be.