Yes, there is such a possibility and it's pretty probable. In your case the best way to be sure is to compare the certificates advertised by a website you use from two separate locations.
Say, if you're a Gmail user, when at home, navigate to https://mail.google.com, click the padlock icon or a green bar to the left of website address, and view certificate details. Look for who issued the certificate (in other words, who is the Certificate Authority - CA). For example - CA for mail.google.com is Thawte.
Also, note the SHA-1 key hash of the certificate (it's a long string of numbers and letters). For mail.google.com this should be "68 AC 69 DF BE 72 B3 0D 08 0E 54 10 84 FD 78 91 FC BD 6D 9B".
Browse to the same website when at work and just compare if you're seeing the same certificate. If not, technically you're under Man-In-The-Middle attack. The most probable reason is that a proxy server installed in your work environment do enforces SSL decryption to be able to monitor traffic (so technically they can read your passwords, session ids and all the data that's coming through).
If that's the case you'd have to check with your administrator and ask him if it's possible to turn it off. Also check local laws if that is legal, but I suppose it is (it is in my country).
SSL errors could also mean that your computer date is wrong - if it's too far in the past or future (like a year), that would make some of the certificate expired or not yet valid.
Also, you might have a virus infection that tries to decrypt the traffic. Or someone else (your colleague) at your work is trying ARP spoofing attack to monitor your traffic. There are many possibilities, but certificate errors on sites you regularly visit is definitely something to worry about.