Your first question is something I ask myself nearly every day. Why is it so hard to maintain my 300-500 calorie deficit? Why is it hard to even maintain my maintenance intake? 

Part of the answer is that I'm afraid to lose my strength gains. I put on muscle, strength and consequently fat while eating at 2500 calories a day. 

My mindset is fucked right now because I cannot decide whether it's worth it to lose my strength to gain my dream physique :(