It sounds like you did the work for the company while employed by the company.... so they probably own it. But without more details and a law degree, it would be hard to tell. Talk to a lawyer for accurate advice. Laws on this type of thing can vary by location... every state and country can have different laws.
I am not a lawyer and cannot offer good legal advice. My uneducated guess is that whether you own it comes down to 3 key factors:
1) What was in the documents you signed when you first started working at that company. Most employers have you fill out a lot of forms and contracts for the Human Resources department on your first day of work. Sometimes these contracts can have clauses that would apply to this scenario.
2) Did the company pay for it? It sounds like you had meetings on company time. So that suggests they paid for it to some extent, which is definitely a point in their favor. Did write any of the code on company time, or was it on your own personal time? Did you write it on company-owned computers/devices?
3) I am not sure if this really applies, but were you an hourly or salary employee? If you wrote it on clock while being an hourly worker, then it is almost certainly their code. If you were a salary employee without clearly defined work hours, then they might be able to argue any project you did for work was owned by the company, regardless of where or when the work was done (in the office or at home).
If you are serious about trying to establish ownership of this, then you should probably talk to a lawyer before you do anything else. Also, how complex these programs? Are they really worth fighting over?