Your urine being clear is GOOD SIGN. You want it to be clear, that means you are getting enough fluids in your body and it is ridding of all the toxins within. You cannot die from drinking the amount of water you are currently consuming.
A spike in LH and FSH (LH surge) causes ovulation, following a suppression of GnRH. Estrogen levels continue to rise following ovulation and the corpus luteum forms, which secretes progesterone in significant levels and causes decreases in LH and FSH levels.
During pregnancy, menstruation must stop, and so Oestrogen inhibits these 2 hormones. It also acts on the uterus, causing growth of the uterus and increasing the sensitivity of the uterus to the hormone oxytocin which is involved in the processes of birth and lactation. It also inhibits the hormone prolactin, and thus inhibits lactation during pregnancy.