As bomb says, it's very likely you are not getting enough estrogen from a 25 patch to cause enough build up to have a period. This happened to me when my estrogen was too low.
The down side of that, is that if you are not getting enough estrogen for a bleed, then you are likely also not getting enough for bone protection, cardiovascular benefits, dementia protection and all the other benefits of HRT.
Weight gain (from fat) does not happen rapidly or within weeks. It takes many weeks and months of eating more calories than you are burning to put on ANY fat. Weight gain which occurs more quickly is likely temporary water weight as a result of hormonal changes and will resolve itself. It can also be due to insufficient progesterone, which is a diuretic and counters the water retention.
Simply applying or taking hormones does not mean you have optimal levels because there is a huge variation in what women absorb. Unless you test your hormones and ensure they are therapeutic levels, you really are just guessing.... And it's not possible to test P in the UK if you take it orally, so we have to go by symptoms and trial and error.