Royal queen seeds royal dwarf

Hi guys. This is my first grow and it is in a very small cupboard 60cm by 60cm by 60cm. I have a 40w (real draw) full spectrum Led that I think is way too weak but I need to save up to buy a better one. I will have more space in the spring but for now this is the only place I can grow. I have already learnt a lot and made some big mistakes. I tried LST because of my height restrictions but accidentally ended snapping off the top. It was quite early in the veg stage and she seems to have somewhat recovered. I have been using the RQS grow and bloom boost. I have started getting the brown spots in on the leaves and they are looking bit yellow now. I have tried researching this but can't decide if it's a fungal or nutrient problem. I doubt I will get a great yeild but I don't consume much I use it medically against chronic pain and insomnia. Wishing you all happy grows and any advice would really be apreciated.