Black Sicilian alternative responding to d4


Thank you for the comment and great suggestions! Being such a rookie, I have just changed my mainline white and black openings.
I am experimenting with the London system for white... and it's been disastrous. I'm so used to quick development and castle, then attacking from the flank that I have a difficult time transitioning from the long positional play to an aggressive tactical middle game.
With black I have put the sicilian on the back burner for now. I am experimenting with the English B6 and French defenses.
I like the play with these black defenses so far... but, I probably abandon the London if it doesn't start to click soon.
Thanks again for the advise! It sounds very logical to look for a recripical opening so I can stay in patterns and positions I'm familiar with.
I am obviously not a great player, but I sincerely love the game. After many years of being an occasional chess hack, I am finally spending some time to study and actually improve my game.
My current favorite opening when playing white is the English. I have been drawn to the Sicilian when playing black because of the familiar c-pawn beginning and occasional fianchetto on the king side.
Sicilian obviously doesn't work against d4 openings (I don't believe).
What would Sicilian players suggest I study as an alternative when faced with d4? Something with similar structure and theory?
Thank you for your suggestions.