Am I getting taken advantage of?

First off I have just over 2 years experience, one year working for a beer distributing company and about 15 months with current employer. I'm currently running a reefer trailer on a dedicated route and schedule. Have 3 different runs I do in a month with various pickups for back haul. 1st run I have 35-40 deliveries leave Saturday and return the following Saturday as long as hours are permitting. Usually around 3600 miles round trip. 2nd run I have 24-30 deliveries and swap trailers at the end of my portion of the route and return with a loaded trailer for backhaul and sometimes pick up from 1 or 2 more locations. Leave Saturday morning and return Wednesday night with average 2400 miles. My final run is a shuttle down with 1 or 2 deliveries leaving Saturday and back late Sunday night after swapping trailers. This run is around 1100 miles.
Several questions if anyone is willing to give their opinions. I'm paid 3k salary gross and was told I would get 4k salary after the first month learning the route, clearly I need to have a discussion as its been over a year now and not getting bigger checks like I was told (should have got that in writing). I'm only on the road for 15 days a month unless truck breaks down or weather delays. The schedule doesn't leave much room for a side job and there are no benefits or 401k offered. The company I drive for has a contract with the company whose freight I haul, no idea what boss man is getting paid but I know he's getting more off the top with what I'm being paid vs other drivers.
I had to change my living arrangement as I can't afford my own place in my location with my current salary. While I was delivering beer I was making an hourly wage, benefits, cell phone allowance and 401k. Worked Tuesday through Friday so always had a 3 day weekend unless a holiday fell on a work day then we would work Monday instead of the holiday such as Christmas or Thanksgiving and paid time and a half for other company recognized holidays that we worked on. Oh that's right paid vacations 1 week a year after 1 year. Then 2 weeks the next year and 3 weeks maximum the following years.
My 1 full year I worked for the beer company I grossed 44k and was home every night not eating out all the time. My current job is scheduled so I park the same place in whatever city and state I'm in depending on the route. This makes it difficult to be able to stock up on groceries for the trip, thus adding food costs for convenience.
Also I touch every piece of freight on the truck whether its bags of chicken feed or boxed up food items. It's just pulling the pallets to tail of trailer and down stacking items for each customer so its not at all physical compared to unloading a beer truck each day but then again it's not a drop and hook situation either. Freight is anywhere from 18k to 35k lbs. depending on what customers have ordered obviously.
I guess my main question is whether or not this seems like a fair wage? I'm not putting on much for miles each month with just over 7k usually but it sure seems like I'm on the clock when I start my route until I finish. Maybe I'm just not used to living in a truck half the month and shouldn't be second guessing my salary but it's hard to cover my bills back home and pay the expenses I have while on the road especially since I'm just a company driver and can't claim any of my expenses as far as I know.
Should I consider looking elsewhere for work if I don't get a bump in my pay soon? Am I just that low on the totem pole in the otr side of trucking, not sure what this type of work is considered. Seems like a mix of my beer delivery experience mixed and long haul with less pay.

Please forgive my rambling and grammar, I'm just really stressed out and don't know how to bring this up with my boss. The tractor I'm driving had 14k miles bwhen I hired on last year and he bought another new tractor several months ago to replace an older Peterbilt. I'm sure company money doesn't necessarily translate to money in his pocket immediately but it sure seems like he has lots of fancy toys to play with while he does the business side of things.
Not sure what to think about my situation right now but any ideas or suggestions would be greatly appreciated.

 

Yeah my boss does payroll through a temp agency... not quite sure how that works but thats how I get my paycheck.
Forgot to mention I covered another driver's route the week before Christmas as it worked out I was going to have the week before and during Christmas off because the company doesn't deliver the week of Christmas. I guess since I'm on salary that's like a paid week off. But I didn't get paid until March for that full route I covered. Finally he wrote me a check for $2500 because that's what the other driver makes on that route. It was a couple hundred more miles than my full route but that's more then I take home after taxes in a normal month.

 

Sorry for the unorganized novel but obviously you skimmed through and got the idea. Thank you for the time and reply.

 

Thank you for the advice, might come down to that if I can't get up to par with the other drivers' wages.