Remember that while genetics plays a big part in who you are, you also have the ability to decide this. Work with what you have, and make the best of it. My advice would be to follow the guidelines on how to build muscle mass found in this sub. I'm a hairy guy too, trust me when I say there are some kids who are jealous over the fact that you can grow facial hair and they can't. Do your best to make sure it's properly trimmed. Shave the neck hair, and facial hair all together if you don't want it. You either go all in or all out.
When I was 15 I thought I was done growing too, but I grew a few more inches and stopped a lot later. But really there's nothing you can do about height so why get upset about it? Now your other symptoms kinda remind me of Lyme disease. I'm not really an expert, but it's worth looking in to. Usually hives, poor digestive system, irritable bowel system, having a hard time falling asleep, and most importantly lack of energy, are early signs of Lyme or a co-infection. Don't be scared or anything though it's not extremely dangerous, and can be cured. Again I'm definitely not an expert, or am saying you have it, but I think you or your parents should check it out if those symptoms become a bigger problem.
If you think you're not seeing results, then you need to be working harder. It may be tough but personally the feeling I get after a long workout is comparable to a drug. And I use that feeling as my motivation. I say to myself "I may not feel like doing my workout now, but the feeling of satisfaction I will get once I'm done is far greater than any feeling I will have today." And I do it.
Sorry for the long read, hope it helps :)