I think there's something in my belly!!

I know your all gunna say "contact your doctor" well unfortunately I can not at the moment, if it were an emergency, I would make the time but at the moment I have two incredibly sick kids at home, and won't be able to leave the house till probably next week. So here's what happening, I'm on the pill, period is clock work, comes when it's meant to come, last 2-6 days, haven't missed one. That's the only protection we use. So (I know it's been a long time) for a good 4-6weeks I feel like I'm pregnant! Just with exhaustion, sore boobs, weight gain and I swear something is moving in my stomach! But all negative home tests, I've taken heaps! But they don't feel like full on kicks! All my symptoms also have another possibility. The exhaustion, I have two toddlers, one with special needs, I've been getting up a bit earlier then usual and they are waking during the night again, sore boobs, I am on the pill an I know that can do it, the weight gain, I've always been extremely small, 42kgs.. I'm now 51kgs and that happened in just a couple months BUT I quit smoking last year, I came out of depression and started eating 10x better! And the "movements" could be gas, I do suffer from IBS a little bit but lately due to everything improving in my life it seems to be fading off too! So my question is, what do you think? Is it possible at all for me to be pregnant? It seems crazy to even ask considering I get my period and negative HPTs. My partner and I plan to start trying in a month so I'm honestly not bothered either way!
Thanks! :)