ur MMR isnt near silver. the system wont let ur rank raise to silver until u get ur MMR up there as well. u have to win more games overall.
dont complain about it tho, some of us have LOST LP FOR A WIN after a losing streak. its called clamping. u see my winning streak put me way high up (i won all my games in silver 2 after promotion and went straight to silver 1) so when i lost a few games the system thot it moved me up to quickly. even after i turned it around, the system wasnt convinced, i had to keep winning in order to prove myself. its called hard work. its nothing to be afraid of.