Starcraft 2

after 3 months of inactivity, two race changes (zerg -> protoss for a few weeks -> zerg), and just overall being busy, i am now a high bronze zerg. (well that's mostly the fault of my friend who's been playing on my account for the past 2 months, i was a mid-gold protoss). i've been playing a lot this week, i easily stomp high silvers and low-mid golds, so i expect to move right back up to gold. i have two key weaknesses: marine/tank/thor and marine/tank/starport.

i cannot counter marine/tank/thor for the life of me. all my losses are to this build. with terran i almost always pump out lings and blings the minute my lair finishes and take 4 gas, then save up for mutas. i think my problem with marine/tank/thor or starport pushes is that pushes normally come later than just marine/tank/medivac, so i underproduce either mutas or lings. i also don't do much harassing when i see marine/tank in general.

any advice or practice? my ZvP is more or less fine, though i rarely ever deal with colossi in ZvP so i don't know how i would do against them (roach/infestor?). ZvZ is probably my best matchup since it just comes naturally to me.