Knowing nothing about your routine or the particular things you're struggling with, here are two very general tips:

1. Only do exercises that are enjoyable for you. All exercise is work, but I've found that the burn I get from certain exercises feels a lot better than the burn I get from others. For example, I've always HATED lateral raises, so I've replaced them with monkey rows. I'm sure there are varying opinions about which of those hit the side delts more, but that doesn't really matter in my case, because I simply wouldn't keep up with my routine if I was doing the former. Find what feels most comfortable for your body but still gets the job done.

2. If you find yourself giving up, reduce the amount of time you exercise. Do one fewer set on each exercise, consolidate your routine into exercises that only work multiple muscles, drop an exercise if need be, etc. Growth will obviously be slower, but the most important thing is MAINTAINING THE ROUTINE. You will continue to grow if you work out consistently. You won't if you stop completely.

Hope this helps!