My PTS female(s) become 'bottom dwellers' for a week- 2 weeks before giving birth. Consistently the gravid state has been 7-8 months. I set up birth areas on the bottom when mom starts to get close with a heating pad, hide, and small food bowls so mom and baby can be warm, hide, and mom can continue to eat if she wants to. This has worked well for 6 PTS babies born at my house.
If you really want to know if she is gravid (pregnant) or not, find out whether there is one or two- bring her to your vet. Since this is a wild caught animal, having a fecal checked for parasites is also important.
I would recommend working on her diet- it sounds very heavy on the fruit and too light on leafy greens. They are vegetarians/herbivores- not fruit eaters. Just because they like it, does not mean it is the best or an appropriate diet. Pothos is a nice supplement, but I don't think any one green should be the staple. Lettuce has very minimal nutrition, and does not count in my book as a leafy green. Try to get more dark leafy greens into her (mine get about 75%). Good greens suggestions: Kale, Mustard greens, collards, radish and carrot tops, dandelion, chard, mulberry. Also start grating or finely chopping other veggies into her food such as squashes, yams or sweet potato, carrot, green beans, peas, corn ect. I use fruit to sweeten the mix (squeezing kiwi, mango, apple or banana up) and mixing it in with their vitamin/calcium supplements. You also should be regularly supplementing her food with a quality vitamin D3/Calcium powder. UVB light is also a good idea (mercury vapor lamp or fluorescent tube).
Cheers, jess b