The difference is that "SO" is emphatic, affective ("subjective") and similar to a tacit demonstrative (= to TH-(is) extent, where the referent of TH- may be left implicit), whereas "TOO" is factual ("objective", not affective), and has no demonstrative content, it simply means "to a greater extent X than appropriate [for X]" (where X = a quantity or a property of a thing [adjective] or event [adverb]).
A proof of the subjective/objective difference between them is that you can use emphatic affective constructions like (1), but not (2):
(1) "So much did I want those Manolos, that I invested a month's salary in them."
(2) "*Too much did I want those Manolos to worry about their price."
There is also a sociolinguistic difference. Women often use an emphatic, affective, demonstrative "so" where men more soberly use "very", which is not intrinsically emphatic, nor "affective", nor "demonstrative", but "objective", cf. (3)-(4)
(3) "She is SO clever!" [Female] vs. "She is very clever" [Male], or
(4) "I like him SO much!" [Female] vs. "I like her very much" [male]
[This is what Sonia refers to, I suppose].
In such cases, women use "so" (as you did) without the "that+[result]" clause that normally follows (which is left implicit, to be determined by context), but, in general, the clause is necessary, and its function is to indirectly specify degree by mentioning a situation that may give the hearer an idea of the intensity or excess involved. This reveals another difference between "SO" and "TOO": After "SO", the clause is a factual result clause, as in "I loved her so much that I gave up my career for her" (Fact: I did give up my career), whereas after "TOO" the clause is a "to" infinitive with "negative" import, i.e., it expresses something that is NOT the case: "I loved her too much to worry about my career." (i.e., I did NOT worry about my career).
I hope this answers your question.