How can I get emails coming into the correct account and be able to send responses, as well as new messages?

When I returned from a 20-day vacation, I had a message that “Thunderbird had a problem and crashed. We’ll try to restore your tabs and windows when it restarts….” I do not know when the “crash” happened. However, I have had problems with my 5 AOL email accounts and sometimes the 3 GMAIL accounts since August 20. The AOL accounts are the worst problems. Emails from one account are coming through under a different email account. This is happening with two accounts. Emails for one of the accounts is not coming through at all. I can read messages; but I cannot send any messages through any AOL account. Sending messages through the GMAIL accounts is sporadic in going through. Although my husband and I have separately checked all TB menu items, tools, & settings, we have not found the answer to correct my problems. Any help is appreciated.