what about the letter that says my license is suspended, how do I take care of that?
You need to follow the instructions in the letter and contact your company or agent about the problem.  Ask your company to file a notice of coverage with the DMV electronically.
what happens if I let my insurance lapse for some time but I have insurance now?
Once the lapse is determined, the registration and, if the lapse period is 91 days or more, your driver license will also be suspended for the same number of days. The suspensions may not be effective on the same date.