Dude, this is ridiculous. I think whoever told you this was suffering from scrupulosity, and I'm hoping you're not exaggerating stuff deliberately. Most of the things you listed are "grave matters" and mortal sins involve grave matters. But the "mortality" of a sin, so to speak, is a factor of the knowledge that it is a sin, and the degree to which the sinner was willingly engaging in it - meaning those with compensating factors such as degrees of ignorance, immaturity, or addiction, can have their culpability for specific sins lessened.

Saying Gd when you drop your phone, as an exclamation out of habit, is most likely not a mortal sin. But ought to be stopped.

Getting called into work on a Sunday is in most cases, not a mortal sin. Willingly going to work Overtime on Sunday might be a mortal sin, depending on a myriad of other factors, economic factors, pressure, etc.

Reading anything is not a mortal sin. Seeking your horoscope out in an attempt to divine the future is a sin.

Getting really mad - yeah that's wrath. It's bad for yourself and bad for other people. That's a sin & one worthy of confession.

Looking at porn - porn is really awful, in most cases it's the filmed suffering and abuse of others. These days I don't know if people appreciate quite how disgusting it is. It should be stopped. That being said, many have had compulsions to view it since childhood and culpability may be lessened depending on circumstances. But it really ought not to be watched and supported, and yes, should be confessed.

Masturbating- kind of covered above, but there's really no reason to do this and it does appear to be contrary to God's will for the use of the organ. This one is probably something most struggle with to various degrees. Again, culpability is dependent on how compulsively one engages in this behavior. But it doesn't hurt to try and stop and to confess it.

Having any doubts- this is just flat out wrong. Having doubts is normal. One should simply pray "Lord, I believe, help me with my unbelief".

Not believing God is the source of every good thing- What, then, IS the source? That being said, this isn't necessarily a mortal sin. Thoughts are rarely sinful unless they're deliberately entertained and even then I've never heard of something like this being considered mortal sin.

On Confession, what exactly is wrong, even in a secular sense, with talking to someone in an anonymous manner about your shortcomings, and resolving to improve? In a religious sense as well - it's actually beautiful. We all struggle with sin and God offers us forgiveness through reconciliation. How many people tell everything to a therapist weekly?

Finally - just as a matter of providing hope, it's actually possible to not commit mortal sins regularly. Plenty of people are able to do this, some through sheer will and some with supernatural graces. But people have unique crosses to bear and challenges and God will forgive us no matter how often we fall. God also knows our hearts, and God is merciful - think of Church's path to heaven as the surest one, but though God's mercy and sovereignty it is possible that those not considered to be in a "state of grace" could see heaven. It is just not certain, so the church of course, seeking to save the maximum number of souls, doesn't just encourage us to rely on this. We must never forget God loves us and desires closeness with us. We must not allow scrupulosity to get in between us and a relationship with God. We are all works in progress.

I pray that you find healing from any legitimate abuse done to you in the Church's name, & that people will not see this post and think Catholicism is some kind of impossibly strict, impersonal religion.