Alarm Horn and car un-locking its self

[Phantom]

About two weeks ago I changed my spark plugs and wires and it just happens that the fob battery died (only one I have)when doing this because it no longer locks or unlocks the car. Luckily the car was unlocked so I did not have to deal with the alarm going off.

This morning just before 7am I was leaving for work when my car alarm was set off by me opening the door I drove off since I did not want to wake the neighbors any more so. On the way to work I stop to get gas the alarm goes off when I open the door, it goes off again when getting back in and when getting out at work.

I do not know how the alarm got set I use the lock button on the door like I have been doing for the last two weeks with no issue. How can I disable the alarm or the horn for the alarm only?

I'm not sure if this is relevant or related but I have noticed in the past that occasionally the car will unlock the car on its own. Like I will lock the car then hear it click and be unlocked, I have only really noticed that happening on/after long drives once it kept unlocking its self as I sat with the car running talking to a park ranger.