Zerg help needed. Stuck and can't move on...

Hey guys I've been playing a lot of games these past weeks as zerg. However, I've ran into a couple of problems though with my gameplay. My league rating is high silver/low gold. I have watched replays and it seems as if I'm stuck at this one point where i am unable to win any more games. Here are 2 replays if you guys could please help me out with what I'm doing wrong. I keep my minerals low but I'm still getting raped...

This one is me against protoss: http://www.sc2replayed.com/replays/66925-1v1-protoss-zerg-steppes-of-war

This is one against terran ( very short)-http://www.sc2replayed.com/replays/66926-1v1-terran-zerg-scrap-station

 

I'm mid platinum player, so my advice will not be pro like, but it will help you. I have found several errors on your side. Only watched the replay vs toss.

First, you expanded too late. The protoss even expanded before you, they usually do so later because they need less bases than zerg. Second, after your initial 2 zerglings died, you sent another two to the watchtowers (good), but did not keep contact with your opponent's base exit. Always have a ling guard it and look from time to time what he masses.
You did not scout his inner base. You could have suicided an overlord, or morph into an overseer to drop a changeling and see what's going on.
Next, you did not counter. You saw he was massing zealots+stalkers, so you should have gone roaches+hydras with speedling support, instead you dropped an expensive spire which did you no good. Give up the mutas vs protoss, they usually have tons of stalkers and oversaturate their minerals anyways. You may drop a spire later in the game, if you think he does not expect air and it could hurt him, or if he attacks with colossi, against which you should build corruptors. If you want to be mobile, which you need, you should either research quick overlords which can do drops (both upgrades available at lair) or build nydus worms on strategic points, and finally in his base (air unit for needed sight), and quick kill some buildings.

Next, your 3 hydras you sent when you saw him expanding were meant to be killed. Mass your units, scout your opponents masses before you send in units, there's no use suiciding units, you wanna do more damage than you take.
When you attacked his 2nd expo (which was good, but at that point you should have gone for your 3th already), you shouldn't have left klicked the pylon. 2 thirds of your zerglings were dancing around bc they didn't get a spot to attack. Basically, you need to learn to utilize the attack move. With your units selected, press a+left click. Your units will move there and attack anything in their way. If you would have done that, the dancing speedlings would have attacked the other pylon instead.

Also, you started way too late to spread creep, you should build your 2nd queen before your first expo, to spread creep and to defend against possible air rushed. Talking about air, once you had seen his phoenixes, you should have sent all your overlords back to base where they can't be sniped and built more queens or hydras exclusively for base defense. And basically you should build an evo chamber quite soon, especially when you have no intel about his base some minutes into the game, he could go void rays or phoenixes and then you need spore crawlers badly.

I think that's all that came to my mind

 

So in games from now on. Should I only drop a spire when needed and make mutas or just specifically make hydras/roaches

 

i have the same tendency to want to drop mutas bc im obsessed with muta harass, therefore bypassing my hydras until later in the game. i know its not a good thing though because i've been on a massive losing streak!

thanks for the tips dom!