We still aren't sleeping!

My precious son went from sleeping 7-8 consecutive hours at night to sleeping for 2-3 his at a time once we hit four months. Now it's getting worse instead of better! I haven't slept for more than 90 minutes at a time in three weeks. He just turned 5 months on the 7th. Has anyone come out of the four month sleep regression yet? Have they seen an improvement? I'm losing my mind.