It's really hard to make a truly "doomed" build as long as you don't actually doom it on purpose (like a 3 WIL psi build). Bad choices can be a major handicap but mistakes are a part of the experience.
My goal was to be a stealth based guy who uses snipers and pistols
That just happens to be my favourite build to play too.
S 5
D 10
A 6
C 5
P 7
W 5
I 3q
It's not perfect, but not that terrible either. Definetly salvageable.
STR is fine. Just enough for all sniper rifles except for one unique towards the end of the game that needs 6, but frankly it's not worth it.
DEX is a little too high in my opinion, unless you want to focus on pistols more than snipers. 7 is my sweet spot on sniper builds with pistols as a secondary, just enough for Gunslinger.
AGI is fine, 6 is just enough to pick Sprint feat.
CON is fine as well. Some people go for 3, but I usually go with 5 just like you did. Extra HP is always nice.
PER is the biggest issue here. You need 10 for Snipe and Sharpshooter feats, both are absolute must have for snipers and high PER is general benefits them a lot. You get 1 new attribute point every 4 levels so you can salvage this, but it will take a lot of time. I usually start with 10, at least 9, and end up with 15/16 by the end of the game.
WIL is too high. There is little reason to go above 3 if you're not using psi, maybe 4 if you want to avoid a penalty to persuasion/mercantile/intimidation.
INT is pretty low. Snipers really benefit from crafting their own rifles and goggles. I wouldn't go below 5, 7 if you want to take crafting feats.
My feats so far are Aimed Shot, Expertise, Gunslinger, and Escape Artists.
That's alright. I would take sprint too, it's really great for that kind of build. As a matter of fact it's great for everyone.
I am fine with changing how I play this character, but if I have made to many mistakes I would rather start over now instead of getting 30 hours in before I relies I can't finish the game.
You should be able to finish the game if you spend the next 3 attribute points in PER. You really want to have Snipe and Sharpshooter as a sniper.
If you want to start over, just make sure you DEX is at least 7 and PER is as high as you can afford, start with 9 at the very least and bump it to 10 at level 4. That's all you need for a sniper/pistol build.