Weight gain tips/advice for skinny guy?

I'm a 20 year old dude who has been pretty underweight my whole life. I'm 6'1" and naturally fluctuate around 135lbs. I'm a union carpenter doing pretty heavy duty gang formwork at least 40 hrs a week; lots of climbing and pretty heavy lifting. I love my line of work, but I've always been self-conscious about my body. Being so underweight makes me feel like less of a man and I'm likely to wear pants and longsleeves year round, even if I'm sweating my balls off, just to hide my figure a bit. To put it in perspective, I wear size 30x34 pants if I can even find them in that size.

I've been in and out of the gym for years now, I can never keep it consistent simply because I don't have the energy to do so. I've experimented with different mass gainer supplements, as well as making my own "bulking" shakes (whole milk, banana, peanut butter, protein, the typical assortment), but nothing seems to be sustainable for me. At the moment, I'm in a kick of "eat until you're full, all day, every day, whenever possible--and then eat more." So I'm going to monitor how that goes. However, getting the 3500+ calories that I need to gain weight in solid food is obscenely difficult for someone my size, so I pretty much eat whatever I can, including McDonalds, a lot of Jimmy John's, pizza, and other fast foods that are convenient when I'm crunched on time and energy. I'm well aware of the adverse effects of a poor diet, and I try to balance it out by eating good whole foods and staying hydrated (water, not soda) as well. I make sure to get plenty of protein in too, whether it's straight chicken breast, or protein bars and supplements. It's just what works for me in order to try and reach my goals.

I guess the reason for me making this post is because I have never been able to find anyone as skinny as me on the internet who is reaching out for answers, and I've given up trying to figure it out myself. So for those who may be interested in helping, here's the short list of questions I have.

1. Should I chill out and accept that I am ridiculously skinny? Maybe get therapy?

2. Is my active profession enough to keep me in shape as I'm trying my best to gain weight by any means necessary? Or should I get more consistent at the gym on top of it?

3. What food items should i buy in bulk? Minimal cooking would be great since I'm usually exhausted after work, but I understand it's pretty necessary in most cases. And more economic.

4. Where do babies come from?

5. Since I am so lanky, if I gain a bunch of weight, is it likely to accumulate in my gut rather than anywhere else?

I just need to hear from real people on this. Getting it out there at least makes me feel a little better.

TLDR; skinny libtard needs to gain weight, running out of options; need advice.