Am I gaining muscle the right way?

I am a college student and I started working out 10 weeks ago. Before that, I only ran 2 miles a day (at about 6:30-7 minute mile pace). So it’s been 10 weeks now and somehow I have not seen any progress in building muscle. I am a 5 foot 7 inch tall and weigh 135 lbs. I also have a flab under my stomach and it seems like I can not get it off of me.

this is what i do for workouts:

3/4 mile warm-up run
1/2 mile run (at 6-6:30 pace)
ab exercises
bicep curls/triceps pulldown machine/lateral exercises
3/4 mile run back to my dorm

total duration- 1 hour and 20 minutes a day

i used to do that routine for 6 days a week. When it comes to doing curls are any machine exercises, i do everything i can to lift good enough to do 3 sets of 10 reps. Recently I stopped doing upper body workouts for 6 days a week but reduced it down to 3 days a week and started working on my legs. somehow in 10 weeks, i have only gained 3 pounds of weight which seems a little too low.

my diet-

cereal with milk, eggs, sandwich, meat, protein drink, etc. i consume up to 2000 calories a day. however i only consume about 4 cups of water a day because i do not want to constntly go use the restroom. i think that is the worst thing i am doing right there when it comes to building muscle.

basically my goal is to get big arms with good pectorals and six pack abs. somehow it seems like i’m not making progress and feel like i need to give up. is there something i am doing wrong? i noticed that i have been using hte asme weights for the past month and they are still very difficult for me. is it because i do not get enough rest or am i not doing something right in terms of working out?
i have heard that an excessive amount of cardiovascular exercise such as long distance running can actually destroy muscle tissue? I used to be a cross country runner and it came to me that it seems impossible to be a big armed muscular long distance runner. am i doing too much cardio so that’s why i am not gaining muscle?