I've been contracting for 40 years, have 65 employees. What you have is a good problem, you just need to get it under control.
1. Separate work life from home life. I'd suggest moving your place of business out of your house. Do your work at work, close the door when you are done for the day and leave it there.
2. Set some hours and boundaries. Do not take business calls, texts or emails during personal time, do not work on estimates after hours, etc. Keep separate work and home phone, email, etc.
3. You can't do it all. Hire some help to do the day to day grunt work so that you can be working on your paperwork, rounding up materials, meeting clients, etc. during normal daytime hours rather than evenings. Pay your help well and make it attractive to work for you. Also, use subcontractors for specialty work.
4. Reasonable rate increases aren't a problem, but don't get silly with your rates if you are satisfied with how it is working. However, don't be afraid to turn down business rather than get yourself overloaded. Taking on too much will get you in trouble.
5. Learn accounting basics and meticulously track costs so that you know exactly what your true cost of doing business is. do not intertwine business spending with personal spending.
Best of luck, looks like a great opportunity.