You could carry a lot based on standard rules
Page 176 of the Player's Handbook states the following:
Carrying Capacity. Your carrying capacity is your Strength score multiplied by 15. This is the weight (in pounds) that you can carry, which is high enough that most characters don’t usually have to worry about it.
Push, Drag, or Lift. You can push, drag, or lift a weight in pounds up to twice your carrying capacity (or 30 times your Strength score). While pushing or dragging weight in excess of your carrying capacity, your speed drops to 5 feet.
Size and Strength. Larger creatures can bear more weight, whereas Tiny creatures can carry less. For each size category above Medium, double the creature’s carrying capacity and the amount it can push, drag, or lift. For a Tiny creature, halve these weights.
You have a strength score of 20, which would give you a carrying capacity of 300 pounds.
Taking into account that your two-handed glaive weighs 6 pounds, your chainmail armor weighs 55 pounds, each javelin weighs 2 pounds, and each spear weighs 3 pounds, we can do the math.
With the glaive and chainmail equipped, you could carry 119 javelins or 80 spears separately. If you wanted to carry both, you could carry 59 javelins and 39 spears together.