Need help with particles to understand sentences

Question

first english is not my mothertongue, so if i make mistakes, correction are welcome. i'm reading an adult light novel and have some problem translating and understanding precisely two sentences. First i will give the whole paragraph for context:

自分の身体すらも認識することのできない、心地良い浮遊感。まるでゆりかごに揺られるかのように、ゆっくりと、 その意識は傾いては元の位置へと戻る。奇妙な感覚ではあったが、 それは決して不快ではなかった。すでに記憶にはない、母の胎内というのはこんな感覚なのだろうか、とぼんやりとした思考が生まれて、そして流れていく。

The first phrase i don't understand is this sentence:

まるでゆりかごに揺られるかのように、ゆっくりと、 その意識は傾いては元の位置へと戻る

It's not that i don't understand the vocabulary,i understand it very well. It's about the two particles i marked in bold, と and へと, especially へと which giving me trouble in understanding the phrase and translating it precisely in my head.

The second i cannot translate it in my head at all, i don't know if it's because i got troubled with that other phrase but i really cannot understand the phrase. It's the phrase which I put in bold above:

すでに記憶にはない、母の胎内というのはこんな感覚なのだろうか、とぼんやりとした思考が生まれて、そして流れていく

Why are there two は particles in the phrase? Can someone help me please?

Answer 1

1. と after ゆっくり is "the optional と". This is a FAQ.
   • What does adding と after an adverb do?
   • What is the purpose of adding と?
   • What role does と play in this sentence?
   • usage of と in this sentence
2. と after 元の位置へ is explained in this question.
   • Particle と with へ; ～へと
3. すでに記憶にはない is a relative clause that modifies 母の胎内. "The internal of Mother's uterus, about which I no longer have memory." The first は is は used with negative clauses. 「すでに記憶にはない、母の胎内というのはこんな感覚なのだろうか」 is the content of his 思考.
   • Why is the topic marker often used in negative statements (ではない, ～とは思わない)?