From my understanding you would retain your current status or title. Such as a Mayor marrying a Count, the mayor will not loose the title of Mayor or the Land. They could either help govern the county or remain and govern the town. They may earn a honorary/bestowed title though marriage though it may be seen as illegitimate and them not being a true noble, just an aristocrat.
Why would not not be able to create your own coat of arms? Most are Family Crests that have been adopted as one representing a County/Dutchy/Kingdom. Your custom Surname will be in place as well though your name may change after marriage. Going into your next life your custom family surname would apply not your past name until you marry again. Sure the child would have your past married name but once you take over the heir I feel the name would change.