General example of base phase. Can modify it to find rhythm and mileage what works best for you. You have plenty of speed already to get to 1.55 or much faster but you lack endurance, although your 5k shows that you have some natural endurance, so you will benefit training frequently at multiple intensities and decent mileage. Once base phase is over cut the volume a bit and add aerobic and anaerobic power workouts and/or race yourself fit, racing at various distances. Maintain the sessions of base phase, just do less, can do more combo workouts if racing weekly or so.
WEEK 1
M Rest / easy run / cross training
Tue Drills + ~50-150m sprints (can use hills/mixed) /~2-5´rec, circuits/weights. Easy run
W Progression run / LT workout / Tempo workout. Easy run
Thu Medium long run / doubles
F Easy run (circuits/weights)
Sat 800m-1600m workout, can use hills. No longer than 200m / ~30s @ 800m or 300m / ~45s @ mile pace/effort. Jog rec (1:3/1:2). Can include LT work. Easy run
Sun Long run
WEEK(s) 2 (+3)
M Rest / easy run / cross training
Tue Drills, ~50-150m sprints (can use hills/mixed) /~2-5´rec, circuits/weights. Easy run
W Progression run / LT workout / Tempo workout. Easy run
Thu Medium long run / doubles
F Easy run (circuits/weights)
Sat 10k-3k workout + ~5x200 @ 800-mile pace. Can include LT work. Easy run
Sun Long run
Every 3-4th week mileage around ~70-75% of normal, include rest day(s).
Increase the mileage/intensity after ~6-8 weeks and stay there ~6-8 weeks until possibly increasing again.