It's not an issue with you, it's just an issue with the hero.
http://www.dotabuff.com/heroes/beastmaster As you can see he has no real identity or a profile, just blink aghs and necro cause you are the summon lord. I wouldn't do mek because of how mana reliant you are and that insane nerf really hurts you.
I feel like ever since Tinker, doing anything with ancients is gonna be non-existant. I haven't seen tinker in a long time and I randomed BM the other day and they warded my ancients instinctively
I couldn't even go in lane! Everyones been getting these huge buffs and BM's been kinda left in the dust, the small ulti buff is nice but he needs a str or int buff or something. He was kinda like WK where his starting stats made him a pretty good early tanky hero but it's fallen off.