Its only been 3 months so We haven't been dating very long at all. I'm 31 and she is 53 and lately after nights when she spends the night and goes home when i leave for work I'll notice stuff missing. At first it started with my medical marijuana....I keep all of my stuff in a drawer where it's out of site, but after a few times where she spent the night and would wake up before me I'd notice my stash was starting to look a bit light. When I said something to her about it she pretty much brushed it off and acted like I got too drunk/wasted and probably smoked a lot. However, on that particular occasion I recall only having one alcoholic drink before bed so I KNOW I wasn't as fucked up as she was making it out to be.

A week or so goes on and we hang out the following weekend. I start monitoring my stuff more closely including the money in my wallet. It was a Saturday and I remember before she came over I counted $48 in cash (a 20, two 10s, and 8 singles) the next morning a 10 dollar bill is missing out of my wallet. When I confronted her about it she didn't get defensive or anything and acted like I lost my mind. She gaslighted me into believing that I must have miscounted...but I know how much I had. I get that it's only 10 bucks but it's the principle of the fact...ive told this woman time and time again if she needs anything just ask!

Flashforward to a couple days ago when she stayed over: I had literally JUST went grocery shopping the day before she came over to stay. Check my freezer just now to pull out a tray of chicken and notice at least HALF of the meat I bought is gone. She's the only person who's been in my place so I know she stole from me and I know when I confront her about it she's going to have some bullshit lie ready for me on the fly. The food thing I don't even fucking understand! She gets food stamps, whereas I don't get any kind of benefits like that because "I make too much money" so what little food I have comes out of my own money.

If anything I'm more disappointed in myself than anything else for falling for this shit with yet another user and I plan on ending this shit but I don't really know how to approach it in a calm manner without being hostile towards her?

TL;DR- My gf is stealing from me, gaslights me when I've approached her about it. Any advice would be much appreciated.